alleles, genes and phenotypes Flashcards
what does wild type mean
the allele that is common - thought of as default phenotype
what does polymorphic mean
a gene with multiple alleles
what is codominance
two alleles that produce different phenotypes are both expressed
what is a pleiotropic allele
has multiple phenotypic effects
what is epistasis
phenotypic expression of one gene is influenced by the products of other genes
what is penetrance
the proportion of individuals with a genotype that develop the expected phenotype
what is expressivity
the degree to which a phenotype is expressed in an individual
what are qualitive traits
those with discrete qualities often controlled by alleles at a single locus
what are quantitative traits
those showing continuous variation can be influenced by genes at many loci as well as by the environment
what is the violation of the law of independent assortment due to
genetic linkage
how do you calculate recombinant frequencies
number of recombinant offspring / total number of offspring
when are recombinant frequencies greater for genes due to the likeliness of an exchange event
exchange more likely between genes that are further apart
what can recombinant frequencies be used to infer
the location of genes on a chromosome + make genetic maps
what is the homogametic sex
has 2 copies of the gene
what is the heterogametic sex
has 1 copy of the gene
what is hemizygous
a gene that’s present in a single copy in an otherwise diploid individual
what is lyonization
early in embryo development, 1 X chromosome inactivates by supercoiling to a Barr Body
what is incomplete dominance
heterozygotes with a “blended” phenotype
