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16 Cards in this Set
- Front
- Back
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what is a locus?
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location of gene on chromosome
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what's an allele?
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alternative form of gene or DNA sequence at locus
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contrast homozygous and heterozygous:
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homo: alleles @ locus are same
hetero: alleles @ locus are diff |
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contrast compound heterozygous and hemizygous:
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cmpd hetero: 2 diff alleles @ locus are both mutant
hemi: only single copy of gene ex: gene on X chromo in males |
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autosome:
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genes that are on non-sex chromosomes: chrom 1-22
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Sex chromos:
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X and Y chromos
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X-linked
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genes on X chromo
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genotype vs. phenotype:
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geno: alleles present in individual at sp. locus
pheno: observed result of interaction of genotype w/ environment |
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contrast dominant trait and recessive trait:
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dominant: conditions expressed in heterozygotes
recessive: conditions manifested only in ppl homozygous for mutant allele |
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what are 2 main mechanisms that can affect genetic variability?
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locus heterogeneity
allelic heterogeneity |
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what's the variability in the genetic mechanism underlying a disease?
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genetic heterogeneity
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contrast locus and allelic heterogeneity:
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locus: mutations at diff loci result in same clinical phenotypes
allelic: diff mutations at same locus |
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what classification is Ehlers Danlos? cystic fibrosis?
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E. D. : locus heterogeneity
C. F. : allelic heterogeneity |
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what are the rules for autosomal dominant inheritance?
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-gene causing disease is on autosome
- if heterozygous or homozygos for mutant allele, manifest disease -if homozygous for normal allele, not affected clinically -vertical transmission: many generations -ea affected person has affected parent -equal # of affected males and females -male to male transmission -any child of affected person has 50% risk of inheriting disease -if normal family member, don't transmit the disease |
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what are some exs of diseases w/ autosomal dominant inheritance?
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polycystic kidney disease
huntington disease neurofibromatosis marfan syndrome familial hypercholesterolemia myotonic dystrophy achondroplasia |
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what are some features of achondroplasia?
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aoften occurs as new mutation
small stature short limbs large head low nasal bridge prominent forehead lumbar lordosis normal intelligence homozygotes usually don't survive early infancy |
