Genetics Flashcards
what is a gene
biological units passed from parents to offspring
what is co-dominant
both expressed when heterozygous but not to same extent
what is Allelic segregation:
- separation of alleles at locus during meiosis
what is the segregation ratio
- ratio of different phenotypes and genotypes resulting from matings
what is independent assortment
the separation of one locus is independent of another
what is linkage
occurrence of loci on same chromosome
what is epistasis
interaction of genes at different loci -> alleles for one gene influence the alleles for another gene
how is genotypic value measured
- cloning
- measuring performance in many environments
- G value = individuals genetic potential for a trait
what is breeding value (A)
is the ability to pass on phenotypic value to offspring
how to calculate genotypic value (G)
= Breeding value (A – only controlled/known) + dominance deviation (D) + epistatic deviation (I) -> G = A + D + I
- P = A + D + I + E
what is phenotypic variance (Vp)
- extent to which individuals differ in their phenotypic values = average squared deviation of values from population mean for the trait
phenotypic variance formula
- Vp = Vg + Ve
- Vg = Va + Vd + Vi
What is heritability
- the extent to which the phenotypic variance can be explained by the genetic variance
what is broad sense heritability
degree to which variation in a trait is genetically determined
- H2 = Vg/Vp
what is narrow sense heritability
degree to which variation in a trait is transmitted from parents to offspring
- H2 = Va/Vp
- genotypic value
