Flashcards in Genetics: Modes of Inheritance Deck (20)
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1
Autosomal Dominant Disease Homozygotes
Usually lethal
2
Achondroplasia
Dwarfism from AD FGFR3 mut
3
Hemizygous
Males are for all genes on X chromosome
4
Allelic Heterogeneity
Different mutations in same gene may cause the same disease
5
Compound Heterozygosity
2 different abnormal alleles at the same locus in an individual
6
Locus Heterogeneity
Different muts in different chromosomes causing the same disease
7
Sex Limitation
Autosomal dominant disorder expressed exclusively in males
8
Mosaicisim
Ocurrence of 2+ cell lines with different genetic or chromosomal constitutions
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2 Kinds of Mosaicism
Germline - some of germ cells are, mutation transferred to offspring as affected, not mosaic
Somatic - milder/segmental phenotype, cannot be passed to offspring unless present in germline
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Classic Pedigree of Mt Inheritance of Disease
Woman affected, all her children are affected, none of the children of her sons are affected
11
4 Differences b/w Nuclear and Mt Genome
Mt WAY smaller/fewer genes
Mt ring-shaped
Mt way higher percentage of coding DNA
Mt no introns
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Heteroplasmy
An mtDNA variant is found only in a portion of cell's mt
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Homoplasmy
All mtDNA copies have same sequence/mut
14
3 Mitochondrial DNA Point Mutation Diseases
tRNA gene: Mitochondrial encephalomyopathy (MELAS)
ATPase gene: Neuropathy, ataxia, and retinitis pigmentosa (NARP)
ETC Complex 1: Leber's hereditary optic neuropathy (LHON)
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3 Mitochondrial DNA Large Deletions Diseases
Chronic progressive external ophthalmoplegia (CPEO)
Kearns-Sayre (triad of CPEO, bilateral pigmentary retinopathy, and cardiac conduction abnormalities)
Pearson Syndrome (a lot of shit)
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Disease Concordance b/w Monozygotic and Dizygotic Twins by Genetic or Multifactorial Cause
Genetic: MZ 100%, DZ up to 50%
Multifactorial: MZ <100%, DZ less than MZ
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Heritability
Proportion of total phenotypic variance of a condition which is caused by genetic variance
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Threshold Theory of Qualitative Traits
Susceptibility (liability) depends on the combined small effects of many genes and shows a bell-shaped distribution in the population, and only proportion of individuals exceeding a certain threshold develop the disease
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Qualitative vs. Quantitative Trait
Qualitative is dichotomous, quantitative continuous
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