IMED2004 Study Guide - Final Guide: Pupa, Zygosity, Gamete
Document Summary
Heterozygous at both loci with homozygous recessive: Whether alleles in coupling or repulsion determine phenotypes most common in progeny of testcross. = green thorax, brown puparium & purple thorax, black puparium. = green thorax, black pup & purple thorax, brown pup. Note: genotypes of parents are the same! Differences in phenotypic ratios of progeny due to configuration of chromosomes. Predicting the outcomes of crosses with linked genes: Knowing arrangement of genes on a chr. allows us to predict types of progeny that will result from a cross. Determining proportions of types of offspring requires an additional piece of information the recombination frequency. Provides information how often alleles in gametes appear in new combinations and therefore allow predictions of proportions of offspring phenotypes. Cucumber; smooth fruit (t) recessive to warty fruit (t) and glossy fruit (d) is recessive to dull fruit (d).
