BIO-1120: Chapter 15

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BIO-1120: Chapter 15
2015-01-03 20:53:39
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  1. Aneuploidy
    a chromosomal aberration in which one or more chromosomes are present in extra copies or are deficient in number
  2. Barr Body
    a dense object lying along the inside of the nuclear envelope in cells of female mammals, representing a highly condensed, inactivated X chromosome
  3. Chromosome Theory of Inheritance
    a basic principle in biology stating that genes are located at specific positions (loci) on chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance patterns
  4. Crossing Over
    the reciprocal exchange of genetic material between nonsister chromatids during prophase I of meiosis
  5. Deletion
    (1) a deficiency in a chromosome resulting from the loss of a fragment through breakage. (2) a mutational loss of one or more nucleotide pairs from a gene
  6. Down Syndrome
    a human genetic disease usually caused by the presence of an extra chromosome 21; characterized by developmental delays and herat and other defects that are generally treatable or non-life-threatening
  7. Duchenne Muscular Dystrophy
    a human genetic disease caused by a sex-linked recessive allele; characterized by progressive weakening and a loss of muscle tissue
  8. Duplication
    an aberration in chromosome structure due to fusion with a fragment from a homologous chromosome, such that a portion of a chromosome is duplicated
  9. Genetic Map
    an ordered list of genetic loci (genes or other genetic markers) along a chromosome
  10. Genetic Recombination
    general term for the production of offspring with combinations of traits that differ fromthose found in either parents
  11. Genomic Imprinting
    a phenomenon in which expression of an allele in offspring depends on whether the allele is in inherited from the male or female parent
  12. Hemophilia
    a human genetic disease caused by a sex-linked recessive allele resulting in the absence of one or more blood-clotting proteins; characterized by excessive bleeding following injury
  13. Inversion
    an aberration in chromosome structure resulting from reattachment of a chromosomeal fragment in a reverse orientation to the chromosome from which it originated
  14. Linkage Map
    a genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes
  15. Linked Gene
    genes located close enough together on a chromosome that they tend tobe inherited together
  16. Map Unit
    a unit of measurement of the distance between genes. one map unit is equivalent to a 1% recombination frequency
  17. Monosomic
    referring to a diploid cell that has only one copy of a particular chromosome instead of the normal two
  18. Nondisjunction
    an error in meiosis or mitosis in which members of a pair of homologous chromosomes or a pair of sister chromatids fail to separate properly from each other
  19. Parental Type
    an offspring with a phenotype that matches one of the true-breeding parental (P generation) phenotypes; also refers to the phenotype itself
  20. Polyploidy
    a chromosomal alteration in which the organism possesses more than two complete chromosome sets. It is the result of an accident of cell division
  21. Recombinant Type (Recombinant)
    an offspring whose phenotype differs from that of the true-breeding P generation parents; also refers to the phenotype itself
  22. Sex-Linked Gene
    a gene located on either sex chromosome. Most sex-linked genes are on the X chromosome and show distinctive patterns of inheritance; there are very few genes on the Y chromosome
  23. Translocation
    (1) an aberration in chromosome structure resulting from attachment of a chromosomal fragment to a nonhomologous chromsome. (2) During protein synthesis, the third stage in the elongation cycle, when the RNA carrying the growing polypeptide moves from the A site to the P site on the ribosome. (3) The transport of organic nutrients in the phloem of vascular plants.
  24. Trisomic
    referring to a diploid cell that has three copies of a particular chromosome instead of the normal two
  25. Wild Type
    the phenotype most commonly observed in natural populations; also refers to the individual with that phenotype
  26. X-Linked Gene
    a gene located on the X chromosome; such genes show a distinctive patterns of inheritance