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19 Cards in this Set
- Front
- Back
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What are some examples of chromosome mutation?
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Translocation, insertion, deletion
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Which is more deleterious: a chromosome mutation or a gene mutation?
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Usually chromosome mutation
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What can happen if a point mutation is in the coding sequence for a protein?
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Nothing
Altered amino acid Premature termination of protein synthesis |
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What is homozygous?
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Identical alleles of a gene are present on homologous chromosomes
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What is heterozygous?
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Two different alleles of a gene
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What are 5 modes of inheritance that may lead to genetic disease?
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Autosomal dominant
Autosomal recessive X-linked recessive Sex-limited inheritance Polygenic |
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What is autosomal dominant?
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Only one copy of mutated allele needed to cause disease
Relatively easy to eradicate Either AA or Aa Does not skip generation On autosome Rare if lethal |
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What is autosomal recessive?
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Two copies of allele needed to cause disease
May skip generations aa On autosome |
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What is penetrance?
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The proportion of individuals that carry a genotype that express the phenotype
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What may affect penetrance?
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Background genetics (interactions with other genes)
Minor environmental effects |
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What is X-linked recessive?
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If mutation present in males, it will result in disease as hemizygous
Females may be carriers = heterozygous or affected = homozygous |
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What is sex-limited inheritance?
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Mutation found on autosome, however only expressed in one sex
e.g. cryptorchidism |
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What is polygenic inheritance?
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Traits found on many genes, gene interactions + environment lead to phenotype
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What is polymorphism?
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Variation in phenotypes in a population
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What is a wild-type allele?
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Normal, unaltered allele
Typical phenotype found in species in nature |
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What is a loss-of-function allele?
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Gene product has reduced or no activity compared to wild-type by down-regulating mRNA expression or reduced function of product
Frequently recessive |
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What is a gain-of-function allele?
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Gene product has increase activity compared to wild-type by upregulating gene expression, increased product or different function of product
Generally dominant |
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What is dominant-negative allele?
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Mutant allele produces abnormal protein that interacts antagonistically to other peptides
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What is an isoallele?
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An allele that does not change quantity, quality or distribution of product
e.g. nucleotide substitution, amino acid change |
