exam1.txt

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biol334 midterm
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biol334 midterm 1
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  1. CH1
  2. Gene
    the fundamental physical and functional unit of heredity, which carries information from one generation to the next; a segment of DNA composed of a transcribed region and a regulatory sequence that makes transcription possible
  3. genome
    the entire complement of genetic material in a chromosome set
  4. genetics
    1) the study of genes 2) the study of inheritance
  5. DNA Replication
    DNA --> DNA involves proofreading
  6. Transcription
    the synthesis of RNA froma DNA template; no proofreading
  7. Translation
    the ribosome- and tRNA-mediated production of a polypeptide whose amino acid sequence is derived from the codon sequence of an mRNA molecule:::: DNA-->RNA--> protein (central dogma of molecular biology)
  8. Eukaryote
    an organism having eukaryotic cells which are cells containing a nucleus
  9. genetic polymorhpism
    naturally occurring genetic differences between individual members of a population
  10. forward genetics
    a mutation that converts a wild-type allele into a mutant allele
  11. mutation
    1) the process that produces a gene or a chromosome set differing form that of the wild type 2) the gene or chromosome set that results form such a process
  12. drosophila
    FRUIT FLY
  13. phenotype
    1) the form taken by some character (or group of characters) in a specific individual 2) the detectable outward manisfestations of a specific genotype
  14. reverse genetics
    an experimental procedure that begins with a cloned segment of DNA or a protein sequnce and uses it (through directed mutagenesis) to introduce programmed mutations backinto the genome to investigate function
  15. probe
    labeled nucleic acid segment that can be used to identify specific DNA molecules bearing the complementary sequnce, usually through autoradiography or flurescence
  16. genetic determination model
    genetic "blueprint" variation is entirely a consequence of genetic differences that cannot be modified by any change in what we normally think of as environment. The determinative power of genes is often demonstrated by differences inwhich one allele is normal and the other abnormal. In this view, the genes act as a set of instructions for turning more or less undifferentiated environmental material into specific organism, much as blue-prints specify what form of house is to be built form basic materials. Genes are really the dominant elements in phenotypic determination; the environment simply supplies the undifferentiated raw materials.
  17. environmental determinism
    The genes impinge on the system, giving certain general signals for development, but the environment determines the actual course of development.
  18. genotype-environment interaction
    Need to know both the genetic constitution that it inherits from its parents and the historical sequence of environments to which it has been exposed. What an organism will become critically depends both on its present state and on the environment that it encounters during that moment
  19. developmental noise
    variation in the outcome of developent as a consequnce of random events in cell division, cell movement, and small differences in the number and location of molecules within cells
  20. explain the genetic approach to biology
    A gene is a specific region of DNA that codes for a specific product, products that are coded for by DNA are some RNA, products we are looking at are proteins, differences in teh genes allow for differences in the proteins. ...... A gene is a functional region of the long DNA molecule that constitutes the fundamental structure of a chromosome. DNA is composed of four nucleuotides, each containing deoxyribose sugar, phosphate, and one of four bases: (adenine A, thymine T, guanine G, and cytosine C). DNA is two nucleutoide chains held together by bonds between A and T and between G and C. In replicaiton, the two chains separate, and their exposed bases are used as templates for the synthesis of two identical daughter DNA molecules
  21. what are the four properties of information transfer common to all organisms
    Diversity of structure/form which includes the phenotype; must have the ability to reproduce (huge amount of evolutionary change, involves the formation of gametes and fertilization of the egg) mutability (information in the gene is on the DNA, DNA contains all the info, must get replicated, must be able to chang in order to maintain genetic variability in a population) translation (DNA-->RNA-->protein (central dogma of molecular biology) DNA-->RNA is replication with proofreading. DNA--> RNA is transcription with no proofreading. RNA-->protein is translation with no proofreading. Nucleotides-->amino acids. mutations occur in the DNA)
  22. who was the founder of genetics and what did he do
    Gregor Mendel. Was able to work in garden and experiment with peas; careful observer; located 7 chromosomes on peas
  23. explain the molecular basis of genetic information
    It has a double helix-backbone (made up of sugar and phosphate, attached to the sugar at one specific location is a nucleotide, nucleotide holds double helix together (A, C, G, T::: A's and T's hydrogen bond together with two hydrogen bonds::: C's and G's hydrogen bonds with three hydrogen bonds, held tighter together) linear sequential order of four nucleotides that determin the gene and phenotype)
  24. what is DNA replication (big picture)
    two strands DNA helix are genetically identical (strand and it's compliment) complimentary base pair will be polymerized by DNA polymerase FIG 1-4 pg 7
  25. what are transcription and translation in a eukaryote (big picture)
    Transcription is DNA to RNA; Translation is RNA to protein; four nucleotides in RNA; twenty essential amino acids...thenothers; Ribosome- rRNA plus proteins; in prokaryotic, RNA doesn't get translated
  26. explain forward genetics (what is the starting point---what are the goals)
    Start with what you can see: Offspring ratios tell you a part of a story::::::::: Observation of an observed variation in morphology or physiology... aka a variant phenotype (ie albino) then look for a gene that is different. OR a pathway of metabolism and development that may be different. MESSAGE OF BOOK: a forward genetic analysis begins w/ individuals of two ditinct phenotypes. from crosses and an analysis of inheritancepatterns in teh progeny, a gene may be identified. The function of the product of this gene can then be investigated to illuminate biochemical, physiological, or developmental pathways:::::: notes... forward genetics observe phenotypic ratios ofprogeny, deduce genotypes of parents, cross parents of known genotypes, predict phenotypic ratios in progeny, testcross, tester is testing agianst homozygous recessive willt ell if othe ris homo or hetero
  27. explain reverse genetics what is the starting point--- what are the goals
    A reverse genetic analysis begins w/ a normal DNA sequence. By inserting a mutation in the DNA (or comparing it with the DNA of other genomes), we can analyze the function of the DNA sequence.
  28. what is environmental determinism
    The genes impinge on the system, giving certain general signals for development, but the environment determines the actual course of development.
  29. what is genotype-environment interaction
    Need to know both the genetic constitution that it inherits from its parents and the historical sequence of environments to which it has been exposed. What an organism will become critically depends both on its present state and on the environment that it encounters during that moment
  30. explain developmental noise
    random events in development lead to variation in phenotype called developmental noise.
  31. KEY?: what is the hereditary material
    DNA
  32. KEY?:what are teh causes of variation between individual members of a species
    mutations
  33. CH2
  34. parents
    k
  35. F1
    first generation of offspring
  36. F2
    second generation of offspring
  37. crosses
    the deliberate mating of two parental types of organisms in genetic analysis
  38. mutants
    an organism or cell carrying a mutation... mutation= the process that produces a gene or a chromosome set differing from that of the wild type OR the gene or chromosome set that results from such a process
  39. wild type
    the genotype or phenotype that is found in nature or in the standard laboratory stock for a given organism
  40. genes
    the fundamental physicaland functional unit of heredity, which carries information from one generation to the next; a segment of DNA composed of a transcribed region and a regulatory sequence that makes transcription possible
  41. chromosomes
    a linear end-to-end arrangement of genes and other DNA, sometimes with associated protein and RNA
  42. genome
    the entire complement of genetic material in a chromosome set
  43. diploid
    a cell having two chromosome sets or an individual organism having two chromosome sets in each of its cells
  44. 2n
    diploid
  45. haploid
    a cell having one chromosome set or an organism composed of such cells
  46. n
    haploid
  47. homologous chromosomes
    chromosomes that pair with each other at meiosis or chromosomes in different species that have retained most of the same genes during their evolution from a common ancestor
  48. homologs
    a member of a pair of homologous chromosomes
  49. gene pair
    the two copies of a particular type of gene present in a diploid cell (one in each chromosome set)
  50. transposable element
    a general term for any genetic unit that can insert into a chromosome, excise, and reinsert elsewhere; includes insertion sequences and transposons
  51. intron
    an intron; a segment of largely unknown function within a gene. THis segment is initially transcribed, but the transcript is not found in teh functional mRNA
  52. exon
    any nonintron section of the coding sequence of a gene; together, the exons corresond to the mRNA that is translated into protein
  53. single-gene inheritance
    k
  54. character
    an attribute of individual members of a species for which various heritable differences can be defined
  55. trait
    more or less synonymous with phenotype
  56. property
    a characteristic feature of an organism, such as size, color, shape, or enzyme activity
  57. phenotypes
    1) the form taken by some character (or group of characters) in a specificindividual 2) the detectable outward manifestations of a specific genotype
  58. pure lines
    a population of individuals all bearing the identical fully homozygous genotype
  59. true breeding lines
    a group of identical individual organisms that always produce offspring of the same phenotype when intercrossed
  60. genotypes
    the specific allelic composition of a cell-- either of the entire cell or, more commonly, of a certain gene or a set of genes
  61. cross
    kthe deliberate mating of two parental types of organisms in genetic analysis
  62. allele
    one of the different forms of a gene that can exist at a single locus
  63. dominant allele
    an allele that expresses its phenotypic effect even when heterozygous with a recessive allele; thus, if A is dominant over a, then A/A and A/a have the same phenotype
  64. recessive allele
    an allele whose phenotypic effect is not expressed in a heterozygote
  65. mendel's first law
    the two members of a gene pair segregate from each othe rin meiosis; each gamete has an equal probability of obtaining either member of the gene pair
  66. gametes
    a specialized haploid cell that fuses with a gamete of the opposite sex of mating type to form a diploid zygote; in mammals, an egg or a sperm
  67. random fertilization by gametes
    haploid goes into a diploid.....
  68. single gene inheritance patterns
    k
  69. zygote
    a cell formed by the fusion of an egg and a sperm; the unique diploid cell that will divide mitotically to create a differentiated diploid organism
  70. homozygote
    an individual organism taht is homozygous
  71. heterozygote
    an individual organism having a heterozygous gene pair
  72. monohybrid
    a single-locus heterozygote of the type A/a
  73. homozygous dominant
    refers to genotype such as A/A
  74. heterozygous **gene pair**
    a gene pair having different alleles in the two chromosome sets of the diploid individual--for example, A/a or A1/A2
  75. homozygous recessive
    refers to a genotype such as a/a
  76. genotypes
    the specific allelic composition of a cell--either of teh entire cell or,more commonly, of a certain gene or a set of genes
  77. monohybrid cross
    a cross between two individuals identically heterozygous at one gene pair-- for ex A/a X A/a
  78. genotypic ratio
    k
  79. phenotypic ratio
    k
  80. mitosis
    a type of nuclear division (occurring at cell division) that produces two daughter nuclei identical with the parent nucleus
  81. synaptonemal complex
    a complex structure that unites homologs during prophase of meiosis
  82. meiosis
    two successive nuclear divisions (with corresonding cell divisions) that produce gametes (in animals) or sexual spores (in plants and fungi) that have one-half of the genetic material of the original cell
  83. chromatids
    one of the two side-by-side replicas produced by chromosome division
  84. testcross
    a cross of an individual organism of unknown genotype or a heterozygote (or a multiple heterozygote) with a tester
  85. tester
    an indiviudal organism homozygous for one or more recessive alleles; used in a testcross
  86. sex-linked inheritance patterns
    k
  87. sex chromosomes
    a chromosome whose presence or absence is correlated with the sex of the bearer; a chromosome that plays a role in sex determination
  88. X
    one of a pair of sex chromosomes, distinguished form the Y chromosome
  89. Y
    one of apair of sex chromosomes, distinguished form teh X chromosome
  90. homogametic
    **sex** the sex with homologous sex chromosomes (e.g. XX)
  91. heterogametic
    **sex** the sex that has heteromorphic sex chromosomes (e.g.XY) and hence produces two different kinds of gametes with respect to the sex chromosomes
  92. drosophila
    FRUIT FLY
  93. X linkage
    the inheritance pattern of genes foudn ont eh X chromosome but not on the Y chromosome
  94. Y linkage
    The inheritance pattern of genes found ont eh Y chromosome but not ont he X chromosome (rare)
  95. Pseudautosomal regions
    a region on a sex chromosome that is homologous to a region on the other heterogametic sex chromosome; they act as substrates for meiotic pairing and crossing over
  96. reciprocal crosses
    a pair of crosses of the type genotype A (female) X genotype B (male) and B (female) X A (male)
  97. What are the names of the processes involved in forming Haploid
    Two sequential cell divisions take place, and the two nuclear divisions that accompany them are called meiosis. B/c there are two divisions, four cells are produced. Meiosis takes place only in diploid cells, and the cells that result (sperm and eggs in animals and plants) are haploid.
  98. what are the names of the processes involved in forming the Diploid
    fertilization. When somatic (body) cells divide to increase their number, the accompnaying nuclear division is called mitosis, a programmed stage of alleukaryotic cell-division cycles. Mitosis can take place in diploid or haploid cells. Either 2n --> 2n + 2n OR n --> n + n
  99. what are homologous chromosomes? Are they found in : haploid organisms, diploid organisms, triploid organisms?
    aka homologs. two copies of each of the separately something chromosomes in diploid:::: book! In a diploid nucleus, the two members of a chromosome pair are called homologous chromosomes. The DNA sequences of the members of a homologous pair are generally the same, even though minor sequence variation is often present, which is the basis of genetic variation within a species-- the type of variation that llows us to distinguish one another.
  100. what is another term for gene pairs
    homologs
  101. what is chromatin
    The DNA and associated nucleosomes constitute chromatin, the stuff of chromosomes. Euchromatin (light color staining, less dense) Heterochromatin (dark color staining, very dense)
  102. where are introns and exons located and how do they differ? which is expressed?
    introns- the noncoding regions that interrupt the coding segments of a gene..... exons-...... MY NOTES: intron are pieces of mRNA, in eukaryotic organisms the mRNA has to be processed and the regions nottranslated are interveneing sequences and are clipped out.... EXON-exons are expressed sequences on the mRNA that is trnaslated on teh ribosomes into amino acids
  103. what is single-gene in heritance
    One of the most widely used types of analytical approaches to gene discovery: central components of single=gene inheritance patterns analysis are mutants; single-gene inheritance specific ratios of normal and mutant expression of the property in descendants; tracked at the DNA level
  104. explain mendel's model in modern terms
    Observe phenotypic ratios of progeny: deduce genotypes of parents: cross parents of known genotypes: predict phenotypic ratios in progeny: test cross: tester is testing against homozygous recessive will tell if other is homo or hetero
  105. what is mendel's first law? how does date from his experiments support his first law
    the two members of a gene pair segregate from each other in meiosis; each gamete has an equal probability of obtaining either member of the gene pair
  106. for single gene inheritance patterns give the genotype ratios and the phenotype ratios for a monohybrid cross and for a testcross
    F1: genotype: 1:2:1 (RR, Rr, rr) phenotype 3:1 (red, white) F2: genotype 1:1 (Rr, rr) phenotype 1:1 (red, white)
  107. what is a testcross ad what information can be gained form a testcross
    a testcross will tell what the other allele is.... whether it is homo or heterozygous. It is crossed with a tester which is homozygous recessive
  108. explain sex-linked single-gene inheritance patterns
    all males will depend on the X chromosome from the female.
  109. describe the sex chromosomes for humans and for drosophila
    humans have 46 chromosomes; 22 homologous pairs of autosomes plus 2 sex chromosomes::: homogametic is female and heterogametic is male. Sex determination in drosophila the number of X chromosomes inrelation to the autosomes determines sex: two X's result in a female and one X results ina male. In mammals, the presence of the Y chromosome determines maleness and the absence of a Y determines femaleness. picture on page 63
  110. describe sex-linke patterns of inheritance, hemiygous, sex linkage
    hemizygous (half zygous) The differential regions, which contain most of the genes, have no counterparts on teh other sex chromosome. Hence, in males, the genes in teh differential regions are said to be hemizygous.
  111. be able to describe how the experiments with red-eyed and white-eyed drosophila led to an understanding of X-linked inheritance. why were reciprocal crosses important to that understanding
    Fig on pg 65. Reciprocal crosses between red-eyed and white-eyed drosophila give different results. The alleles are X-linked, and the inheritance of the X chromosome explains teh phenotypic ratios observed, which are differnt from those of autosomal genes. (in drosophila and many other experimental systems, a superscript plus sign is used to designate the normal, or wild-type allele.)
  112. describe human pedigree analysis; symbols, autosomal dominant, autosomal recessive, x-linked recessive, and x-linked dominant
    k
  113. CH3
  114. Genetic symbols used for Drosophila
    k
  115. representation of chromosomes
    / ..... v+/v Two homologous chromsomes, one with v allele and the other with v+ allele v is recessive to the wild-type v+/v +, v+/v, v/v
  116. Mendel's second law
    the law of independent assortment; unlinked or distantly linked segregating gene pairs assort independently at meiosis
  117. independent assortment
    see mendel's second law
  118. true breeding
    see pure breeding line --> a group of identical individual organisms that always produce offspring of the same phenotype when intercrossed
  119. punnett square
    a grid used as a graphic representation of the progeny zygotes resulting form different gamete fusions in a specific cross
  120. product rule
    the probability of two independent events occurring simultaneously is the product of the individual probablities
  121. sum rule
    the probability that one or the other of two mutually exclusive events will occur is the sume of their individual probabilities
  122. branch diagram
    Based on phenotype, Product rule = multiply along the branches
  123. dihybrid cross
    a double heterozygote such as A/a.B/b
  124. test cross
    a cross of an individual organism of unknown genotype or a heterozygote (or a multiple heterozygote) with a tester
  125. chi square analysis
    a statistical test used to determine the probability of obtaining observed proportions by chance, under a specific hypothesis
  126. hypothesis
    Hypothesis Null hypothesis; Reject null hypothesis if differences are due to chance
  127. independent assortment of combinations of autosomal and x-linked genes: drosophila
    at meiosis explains Mendel's ratio:::: Female with vestigal wings (autosomal recessive vg) and a male with white eyes (X-linked recessive Xw) Genotypes of parents Punnett square F1 genotypes and phenotypes F1 X F1 Punnett square F2 genotypes and phenotypes
  128. recombination
    1) in general, any process in a diploid or partly diploid cell that generates new gene or chromosomal combinations not previously found in that cell or in its progenitors. 2) at meiosis, the process that generates a haploid product of meiosis whose genotype is different form either of the two haploid genotypes that constituted the meiotic diploid
  129. polygenic inheritance
    An additive effect of two or more gene loci on a single phenotypic character.
  130. discontinuous traits (variation)
    variation having distinct classes of phenotypes for a particular character
  131. continuous traits (variation)
    variation showing an unbroken range of phenotypic values
  132. quantitative traits (variation)
    the existence of a range of phenotypes for a specific character, differing by degree rather than by distinct qualitative differences
  133. quantitative genetics
    kthe study of the genetic basis of continuous variation in phenotype
  134. environmental factors (variation)
    the variance dueto environmental variation
  135. multifactorial trait (multiple-factor hypothesis)
    a hypothesis that explains quantitative variation by assuming the interaction of a large number of genes (polygenes), each witha small additive effect on the character
  136. hermann Nilsson-Ehle
    Color of wheat kernels Crossed true breeding red kernel plants with true breeding white plants F1 all same intermediate shade F2 15 many shades of red: 1 white 1 dark red: 4 medium red: 6 intermediate red: 4 light red: 1 white Contributing alleles Contribute to the phenotype Noncontributing alleles Not have an effect on phenotype of quantitative trait
  137. Be able to use and work with genetic symbols used for Drosophila
    Letters are chosen on the basis of the phenotype of the mutant allele + indicates wild-type allele Lowercase letter = mutant alleles of gene recessive to wild type w for mutant allele, w+ for wild type allele Uppercase letter = mutant alleles of gene dominant to wild type
  138. work with representation of chromosomes
    / v+/v Two homologous chromsomes, one with v allele and the other with v+ allele v is recessive to the wild-type v+/v +, v+/v, v/v Cy+/Cy Curly, mutant allele is dominant to wild type
  139. Explain and apply Mendel's Second Law
    a. The principle of independent assortment i. Gene pairs on different chromosomes assort independently at meiosis
  140. Begin with true breeding parents and be able to with genetic crosses involving Punnett squares and branch diagrams for the problem types examined in this chapter
    k
  141. Use and apply where appropriate the product rule and the sum rule
    Product rule Probability of independent events occurring together (A and B) is the product of their individual probabilities Sum rule Probability of either of two mutually exclusive events occurring (A' or A'') is the sum of their individual probabilities::::: branch -->Product rule = multiply along the branches
  142. Be able to perform Chi Square analysis
    k
  143. What id the Null Hypothesis?
    Null hypothesis Reject null hypothesis if differences are due to chance
  144. Work problems involving Independent Assortment of Combination's of Autosomal and X-linked Genes
    Dihybrid cross F1 dihybrid x F1 dihybrid Phenotypic ratio 9:3:3:1 Text cross F1 dihybrid X tester Phenotypic ratio 1:1:1:1
  145. What is recombination--and be able to work problems
    During meiosis Crossing over during Prophase I Production of new combinations of alleles Formal definition: Any meiotic process that generates a haploid product with new combinations of alleles carried by haploid genotypes that united to form the meiocyte. :::::Independent assortment produces 50 percent recombinants
  146. Explain Polygenic Inheritance and be able to work problems
    Continuous range of phenotypes because many loci contribute to the phenotype (polygenic) and environmental factors influence a phenotype produced by a genotype
  147. What are Discontinuous traits and what are continuous traits--how are they similar and how are they different.
    Continuous range of phenotypes because many loci contribute to the phenotype (polygenic) and environmental factors influence a phenotype produced by a genotype :::: discontinuous have Distinct phenotypes
  148. What are Quantiative trait?
    Trait that is measured on a quantitative (linear) scale. These traits are typically affected by more than one gene, and also by the environment. Examples of quantitative traits are plant height (measured on a ruler) and body weight (measured on a balance).
  149. What is the role of environmental factors
    Each genotype produces a range of phenotypes
  150. What is a Multifactorial trait?
    Multiple genotypes and environmental factors
  151. Explain the Polygene hypothesis for quantitative inheritance and explain the experiment performed by Hermann Nilsson-Ehle. What are contributing alleles and what are noncontributing allels.
    Hermann Nilsson-Ehle 1909 Color of wheat kernels Crossed true breeding red kernel plants with true breeding white plants F1 all same intermediate shade F2 15 many shades of red: 1 white 1 dark red: 4 medium red: 6 intermediate red: 4 light red: 1 white Contributing alleles Contribute to the phenotype Noncontributing alleles Not have an effect on phenotype of quantitative trait
  152. Explain Inheritance independent of the nucleus involving Mitochondrial (mtDNA and Chloroplast (cpDNA)
    Inheritance independent of the nucleus Mitochondrial (mtDNA) Chloroplast (cpDNA) ????
  153. What progeny ratios are produced by the crosses examined in this and the previous chapter.
    k
  154. Can Mendelian Inheritance explain continuous variation?
    Dihybrid cross F1 dihybrid x F1 dihybrid Phenotypic ratio 9:3:3:1 Text cross F1 dihybrid X tester Phenotypic ratio 1:1:1:1
  155. What are the inheritance patterns involving sex linked genes and of organelle genes?
    Alleles on organelle chromosomes In sexual crosses Inherited from one parent only In asexual cells Can show cytoplasmic segregation In asexual cells Can occasionally show processes analogous to crossing over :::::Mitochondrial mutations associated with certain diseases
  156. CH4
  157. genetic linkage
    the association of genes on the same chromosome
  158. genes mapping
    *map - a linear designation of mutant sites within a gene, based on the various frequencies of interallelic (intragenic) recombination.
  159. syntenic
    *synteny - a situation in which genes are arranged in similar blocks in different species
  160. linked genes
    linked- the situation inwhich two genes are on teh same chromosome as deduced by recombinant frequencies less than 50%
  161. linkage group
    a group of genes known to be linked; a chromosome
  162. recombination
    1) in general, any process in a diploid or partly diploid cell that generates new gene or chromosomal combinations not previously found in that cell or in its progenitors. 2) at meiosis, the process that generates a haploid product of meiosis whose genotype is different from either of the two haploi dgenotypes that consituted the meiotic diploid
  163. chromosome maps
    a representation of all chromosomes in the genome as lines, marked with the positions of genes known from theirmutant phenotypes, plus molecular markers. based on analysis of recombinant frequency
  164. genotypes
    the specific allelic composition of a cell--either of the entire cell or more ocmmonly, of a certain gene or a set of genes
  165. DNA
    A chain of linked nucleotides (having deoxyribose as their sugars). two such chains in double helical form are the fundamental substance of which genes are composed
  166. evolutionary genetic mechanisms
    changes in the genotype reflected in the phenotype, mutants
  167. recombination maps
    a chromosome map in which the positions of loci shown are based on recombinant frequencies
  168. recombinant frequency
    the proportion (or percentage) of recombinant cells or individuals
  169. william bateson
    In the early 1900's, William Bateson and R.C. Punnett were studying the inheritance of two genes in sweet peas. In a standard Self of a dihybrid F1, the F2 did not show the 9:3:3:1 ratio predicted by the principle of independent assortment. They noted that certain combinations of alleles showed up more ofthen than expected, as if they were physically attached... no explanation tho
  170. r.c. punnett
    In the early 1900's, William Bateson and R.C. Punnett were studying the inheritance of two genes in sweet peas. In a standard Self of a dihybrid F1, the F2 did not show the 9:3:3:1 ratio predicted by the principle of independent assortment. They noted that certain combinations of alleles showed up more ofthen than expected, as if they were physically attached... no explanation tho
  171. dihybrid cross
    a cross between two individuals identically heterozygous at two loci-- for ex. AB/ab X AB/ab
  172. thomas hunt morgan
    Found a similar deviation (as if genes were attached) from Mendel's second law while studying two autosomal genes in Drosophila. Morgan proposed linkage as a hypothesis to explain the penomenon of apparent allele association. Morgan performed a cross to obtain dihybrids then followed with a testcross:::: Notes:::::: Studied autosomal genes in drosophila, eye color and wing length. F2 dihybrid X tester male, expected a 1:1:1:1
  173. autosomal genes
    genes found on any chromosome that is not a sex chromosome
  174. F2 dihybrid X tester male
    will result in a recombinant frequency of less than 50% and parental genotypes of greater than 50%
  175. ratio 9:3:3:1 or 1:1:1:1 or neither
    9:3:3:1 is expected when cross a dihybrid with a dihybrid 1:1:1:1 are expected in when a dihybrid f1 female is crossed with a tester Neither occurs when the genes are linked::: genetic linkage affects mendelian gene segregation (9:3:3:1 and 1:1:1:1)
  176. dihybrid testcross results for linked genes
    When two genes are close together on the same chromosome pair (they are linked) they do not assort independently but produce a recombinant frequency of less than 50 percet. hence, conversely, a recombinant frequency of less than 50 percent is diagnostic of linkage.
  177. nonrecombinant classes
    have the genotypes of the parents... will have occur more than 50% of the time
  178. recombinant classes
    *recombinant- refers to an individual organism or cel lhaving a genotype produced by recombination.... have genotypes different from the parents... will occur less than 50% of the time
  179. cis conformation
    in a heterozygote havingb two mutant sites within a gene or within a gene cluster, the arrangement A1A2/a1a2
  180. homolog
    a member of a pair of homologous chromosomes
  181. trans
    in a heterozygote with two mutant sites within a gene or gene cluster, the arrangement a1+/+a2
  182. AB/ab
    CIS conformation
  183. Ab/aB
    Trans conformation
  184. AB/ab Ab/aB
    Alleles on the same homolog have no punctuation, a slash symbolically separates the two homologs, alleles are always written in the same order on each homolog
  185. A/a;C/c
    Genes known to be on separate chromosomes are separated by a semicolon
  186. A/a.D/d
    kGenes of unknown linkage are separated by a dot
  187. mapping by recombinant frequency
    Map units invented by Alfred Sturdevant (1911) a genetic map unit (m.u.) = a recombinant frequency of 1% = one centimorgan:: map distances are generally aditive, longer regions have more crossovers and thus higher recombinant frequencies
  188. map units
    the "distance" between two linked gene pairs where 1 percent of the products of meiosis are recombinant; a unit of distance in a linkage map
  189. alfred sturdevant (1911)
    Invented the Map unit and named the centimorgan
  190. genetic map unit (m.u.)
    the "distance" between two linked gene pairs where 1 percent of the products of meiosis are recombinant; a unit of distance in a linkage map
  191. one centimorgan
    the "distance" between two linked gene pairs where 1 percent of the products of meiosis are recombinant; a unit of distance in a linkage map
  192. three point testcross
    a testcross in which one parent has three heterozygous gene pairs::::: triply recessive tester, (Parents v+/v+.cv/cv.ct/ct X v/v.cv+/cv+.ct+/ct+) gametes, F1 trihybrid, trihybrid females testcross with triply recessive males
  193. triply recessive tester
    v/v.cv/cv.ct/ct
  194. F1 trihybrid
    v+/v.cv+/cv.ct+/ct
  195. trihybrid females testcrossed with triply recessive males
    will give you a 1:1:1:1:1:1:1:1 BUT if linked must look at the numbers of the offspring, ones with lowest recombination will be the ones closest together
  196. interference
    a measure of the independence of crossovers from each other, calculated by subtracting the coefficient of coincidence from 1
  197. coefficient of coincidence
    the ratio of the observed number of double recombinants to the expected number
  198. mapping with molecular markers
    *marker gene* a gene at a well-known locus whose different alleles can be distinguished by some visible phenotype, useful for locating regions containing QTLs linked to the marker gene
  199. map loci of heterozygosity
    is involved with mapping with molecular markers??????
  200. single nucleotide polymorphisms (SNPs)
    a nucleotide-pair difference at a given location in the genomes of two or more naturally occurring individuals
  201. RFLP
    a difference in DNA sequence between individuals or haplotypes that is recognized as different restriction fragment lengths. For ex, a nucleotide-pair substitution can cause a restriction-enzyme-recognition site to be present in one allele of a gene and absent in another. Consequently, a probe for this DNA region will hybridize to different-sized fragments within restriction digests of DNAs from these two alleles
  202. simple sequence length polymorphisms
    the existance in the population of individuals showing different numbers of copies of a short simple DNA sequence at one chromosomal locus
  203. Variable number tandem repeats (VNTR's)
    a chromosomal locus at which a particular repetitive sequence is present in different numbers in different individuals or in the two different homologs in one diploid individual
  204. satellite fraction
    *Satellite DNA* any type of highly repetitive DNA; formerly defined as DNA forming a satellite band after cesium chloride density-gradient centrifugation *satellite chromosome* a chromosome that seems to be an addition to the normal genome
  205. minisatellite marker
    heterozygous locus representing a variable number of tandem repeats of a unit 15 to 100 nucleotides long::: based ont he number of tandem repeats, DNA fingerprints
  206. DNA fingerprints
    the autoradiographic banding pattern produced when DNA is digested with a restriction enzyme that cuts outside a family of VNTRs and a Southern blot of the electrophoretic gel is probed with a VNTR-specific probe. Unlike true fingerprints, these patterns are not unique to each individual organism
  207. microsatellite marker
    a differenc ein DNA at the same locus in two genomes taht is due to different repeat lengths of a microsatellite::: usually repeats C-A and compliment of G-T
  208. how does genetic linkage affect mendelian gene segregation
    they are no longer! the ratios produced are not what is expected
  209. how are genes mapped in eukaryotes
    k
  210. what are the inheritance patterns for genes on non-homologous chromosomes
    (mono is 1:1) (mono self is 3:1) (Dihybrid testcross 1:1:1:1) (dihybrid self 9:3:3:1) (dihybrid linkage something much different) (Tri testcrossed 1:1:1:1:1:1:1:1:1)
  211. what are the characteristics of genes on teh same chromosomes
    Syntenic (a situation in which genes are arrange in similar blocks in different species) inherited together, do not assort independently (different ratios) They exhibit linkage (linked physically together on the same chromosome); linked genes; belong to a linkage group (may be looking at genes for two traits but will be others on the same chromosome); recombination (occurs during metaphase in meiosis)
  212. what is linage, how does it occur, how is it detected
    when genes are linked, they mean that the loci of those genes are on the same chromosome, and hence, the alleles on any on homolog are physically joined (linked) by the DNA between them. Early geneticists deduced linkage by using recombinant frequency,
  213. whta are chromosome maps
    show gene position (build on complex genotypes); structure and function of DNA level; evolutionary genetic mechanisms are changes in the genotype reflected in teh phenotype, mutants
  214. what does it mean to examine structure and function at DNA level? what information can be obtained form examining strucutre and function at the DNA level
    k
  215. explain recombination map
    k
  216. how is recombinant frequency used to recognize linkage
    the more frequent recombinant is further apart, linked alleles are inherited together
  217. what were teh observations of william bateson and rc punnett
    inheritance of two genes in sweet peas with a F2 dihybrid cross revealed NOT the expected 9:3:3:1 ratio but instead a 1:1:1:1
  218. what was the contribution of thomas hunt morgan to the diagnostics of linkage
    worked with drosophila, autosomal genes, eye color and wing length, crossed F2 dihybrid X tester male, he expected a 1:1:1:1 but instead got many different combos and used the percentages
  219. explain dihybrid testcross results for linked genes
    one would expect four phenotypes in a ratio of 1:1:1:1 but instead observe parental phenotypes (two equally frequent nonrecombinant classes together that total >50%) non-parental phenotypes (recombinant classes that are two equally frequent recombinant classes that together total less than 50%)
  220. explain the following: Two equally frequent nonrecombinant classes totalling in excess of 50% and two equally frequent recombinant classes totaling less than 50%
    the results of a linked Dihybrid testcross
  221. how do crossovers produce recombinants for linked genes
    Crossovers produce recombinant chromatids whose frequency can be used to map genes on a chromosome. Longer regions produce more crossovers. It is a breakage-and-rejoining process. A crossover is a breakage of two DNA molecules at the same positiona dn their rejoining in two reciprocal recombinant combinations
  222. be abel to interpret and use linkage symbolisms and terminology
    k
  223. be abel to explain cis conformation and trans conformation. how do these arrangments affect results of testcrosses
    Cis : the two wild-type or dominant alles are present on the same homolog Trans: the two wild-type or dominant alleles are present on different homologs
  224. explain mapping by recombinant frequency
    k.......FINISH and do the problem
  225. what are map units? what is the formula?
    mu = number of recombinants/ total number
  226. what is the contribution of alfred sturdevant (1911)
    map unit! FINISH
  227. explain and be able to work with a three point testcross. how is the analysis performed
    DO THE PROBLEM... page 140
  228. what is a triply recessive tester
    vv.cvcv.ctct
  229. what is the interference, and what is the coefficient of coincidence, and what are the formulas for each
    crossover inhibition of each other = interference, coefficient of coincidence is observed number of double recombinants/expected number of double recombinants :::: interference = 1-coefiicient of coincidence ::: opposite of interference = 1 - observed number of double recombinants / expected number of double recombinants
  230. what is mapping with molecular markers
    Loci of molecular heterozygosity are called molecular markers. Acting as important "milestones" on the map, molecular markers are useful in orienting the researcher in a quest to find a gene of interest. OMG page 146
  231. what does it mean to map loci of heterozygosity
    k
  232. what are single nucleuotide polymorphisms (SNPs)
    when a sequence differs by a single nucleotide
  233. what is an RFLP? what is the appearance of a gel
    two strands, it snips the DNA
  234. what is a DNA fingerprints
    a minisatellite marker that marks based on the number of tandem repeats
  235. what is a tandem repeat
    AAAGAAAGAAAGAAAG
  236. what is a microsatellite marker
    usually repeats of C-A and compliment of G-T

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