Basic Genetics Concepts

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  1. individuals homozygous for the disease allele
    autosomal recessive
  2. most affected individuals have unaffected parents
    autosomal recessive
  3. manifests in males and females equally
    autosomal recessive and dominant
  4. progeny of two affected individuals are affected
    autosomal recessive
  5. unaffected parents with affected offspring may be consanguinous
    autosomal recessive
  6. heterozygotes and homogygotes (often worse) are both affected
    autosomal dominant
  7. affected progeny have at least one affected parent
    autosomal dominant
  8. can typically assume affected parents are heterozygotes
    autosomal dominant
  9. homozygous females and hemizygous males typically affected
    X-linked recessive
  10. Carrier females typically unaffected
    X-linked recessive
  11. Affects males>females
    X-linked recessive
  12. 100 % of sons from affected mothers are affected, 50% of sons of carrier mothers are affected, and 0 of progeny from affected fathers are affected
    X-linked recessive
  13. Anyone with affected allele will be affected
    X-linked dominant
  14. Females heterozygous and homozygous; males hemizygous
    X-linked dominant
  15. Severity of diseases in males>females, male lethality
    X-linked dominant
  16. Incidence of affected females can be > than affected males due to male lethality
    X-linked dominant
  17. 50% of children of carrier mothers will be affected, 100% of daughters of affected fathers will be affected, 0% of sons of affected fathers will be affected
    X-linked dominant
  18. Only males with affected Y are affected
  19. All sons of affected male will be affected
  20. Mostly relate to fertility and/or sexual development, father-son transmission rare
  21. Coeffecient of relationship
    r=1/2degree of relationship
  22. Coefficient of inbreeding
    F=r x 1/2
  23. Law of addition
  24. Law of multiplication
  25. Hardy-Weinberg equation
    p2 + 2pq + q2 =1
  26. Genotype for p2
  27. Genotype for 2pq
  28. Genotype for q2
  29. In the Hardy-Weinberg equation, q is equal to
    the frequency of affected alleles
  30. In the Hardy-Weinberg equation, p is equal to
    the frequency of unaffected alleles
  31. In order for a disease to be considered vertically transmitted....
    every affected individual must have an affected parent
  32. (FCR)(FTR)(MCR)(MTR)

    F=Father, M=Mother, CR= Carrier Risk, TR= Transmission Risk
    Equation for incorporation population genetics into risk
  33. Hemophilia
  34. disease characterized by an absence of clotting factors
  35. Albinism
  36. disease characterized by loss of pigment in the skin hair, and eyes and a tyrosinase (melanin synthesis) defect
  37. disease characterized by a lack of dystrophin protein and is very well characterized (around 2 mil. base pairs)
    Duchenne Muscular Dystrophy
  38. Duchenne Muscular Dystrophy
  39. Sickle Cell
  40. disease characterized by abnormal HGB, causing RBCs to stickle and have low Ocarrying capacity; leads to easy RBC clotting and breakage
    Sickle Cell
  41. Neurofibromatosis
  42. disease characterized by skin spots and optic glioma
  43. Marfan syndrome
  44. disease characterized by fibrillin mutations and tall stature & long phalanges
    Marfan Syndrome
  45. Rett Syndrome
  46. Neurodevelopmental disorder, males usually die if they have it
    Rett Syndrome
  47. Cystic Fibrosis
  48. disease that affects the flow of chloride ions across the plasma membrane; affectssweat glands and glands that produce mucus & digestive enzymes
    Cystic Fibrosis
  49. Achrondoplasia
  50. A form of dwarfism
  51. Down Syndrome
    disease characterized by extra copy of chromosome 21; considered a chromosomal disorder
  52. Polydactyly

    *can present like AR if reduced penetrance
  53. disease characterized by extra digits; notorious for skipping generations
  54. Examples of multifactorial disorders
    Alzheimer's and Hirschprung (disease characterized by GI problems/constipation)
  55. Red-green colorblindness
  56. Huntington's disease
  57. disease characterized by motor abnormalities and personality/cognition changes
    Huntington's diesase
  58. Heterozygotes resistant to malaria
    sickle cell
  59. Tay-Sach's disease
  60. disease characterized by cherry spots on the retina; has a founder effect in Ashkenazi Jews
    Tay Sach's
  61. An easy way to find the probability of not being a carrier in a Bayesian table
    Subtract the probability from 1
  62. The conditional, "not a carrier" side of a Bayesian table is almost always ____.
  63. The main difference between doing AR & AD H-W problems and doing XLR ones is
    it is only necessary to find p & q, not 2pq, because there is no such thing as a male carrrier. 

    • For example, for a carrier frequency of 1/20 in a population of 2000 (1k M, 1k F):
    • (1/20)=p, q=(19/20).
    • (1/20)2 +2(19/20)(1/20)**+(19/20)2

    **carrier frequency=factoring in the female population
  64. formula for the chance of having unaffected grandsons in XLR Bayesian analysis
    1/2 + 1/2 (1/2)# of grandsons
  65. Formula to determine the likelihood of an affected child in Bayesian
    (PC)(TR)(Penetrance (if available))
  66. If an AR Bayesian problem has an unaffected son, you must...
    make two separate tables
  67. The 2/3 method cannot be used if....
    there is more than one affected son.  

    The risk is then 1. 
  68. Reduction in chromosome number occurs during 
    Meiosis I
  69. Segregation of alleles in the absence of recombination occurs during
    Meiosis I
  70. Segregation of alleles if they are subject to recombination occurs during
    Meiosis II
  71. Independent assortment of paternal and maternal chromosomes occurs during
    Meiosis I
  72. Occurs in the germ line cells to produce gametes
  73. Occurs in somatic cells
  74. Not directly related to Mendelian inheritance, but is important for genetic diseases like cancer
  75. Makes exact genetic copies of cells
  76. Cell products have 1/2 of original cell chromosome content and contain a mixture of paternal and maternal chromosomes, at least some of which have undergone recombination
  77. Fundamental to Mendelian inheritance and understanding chromosome disorders.
  78. Disorders that follow simple Mendelian predictions of inheritance
    Single-gene disorders
  79. Disorders that have an environmental component
  80. Disorders that involve the nuclear genome directly
    All disorders BUT mitochondrial ones
  81. Diseases that involve a genome other than the nuclear genome
  82. Disorders that involve the simultaneous mutation of more than one gene in an affected individual
    polygenic and/or multifactorial disorders
  83. Diseases that involve one or more genes in an individual with a normal  set of chromosomes
    All BUT chromosomal disorders
  84. Diseases that involve changes in chromosome number or large portions of chromosomes
  85. 4 Nucleotides of DNA
    A, G, T, C.
  86. Pairings of DNA nucleotides
    AT & GC
  87. After DNA replication, humans have ___ chromosomes.
  88. Has 3 Billion base pairs per haploid genome and 20-25K unique genes per haploid genome
    Nuclear Genome
  89. Has around 16,000 base pairs and 37 genes total
    Mitochondrial genome
  90. Comprised of several nearly identical circular chromosomes of double-stranded DNA
    Mitochondrial genome
  91. Comprised of several distinct linear double-stranded DNA molecules, one molecule of DNA/chromosome
    Nuclear genome
  92. The largely random inactivation and transcriptional silencing of single X chromosomes into a Barr body in females, which happens early in female development.
    X inactivation
  93. Can increase the occurrence, severity, and penetrance of heterozygous females for an affected allele of an x-linked recessive disorder.
    X inactivation
  94. The individual of focus during pedigree analysis.
  95. Empiric risk is calculated using 
    historical/clinical observations
  96. Consanguinuity, selection, genetic drift, new mutations, assortative mating, and new mutations...
    Can cause deviation from HW
Card Set:
Basic Genetics Concepts
2013-09-16 22:45:25

Basic principles of inheritance, pedigree analysis, risk analysis, and population genetics
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