Symbols to Know for Crosses a/a – a is the allele and / represents the two chromatids – there are two alleles for a diploid organism a b/a b – two different genes on the same chromosome a/a ; b/b – two different genes on different chromosomes ; designated separate chromosomes X – symbolizes mating between two different individuals X - symbolizes a self cross – when the hermaphrodite worms fertilize their own eggs + is the wild type or non-mutant form of a gene

Creating a heterozygous male Hermaphrodite Parent genotype Male Parent genotype X Male gametes Female gametes Progeny genotype Which progeny are you continuing with? Why? Progeny phenotypes and ratios +/+ dpy/dpy

Hermaphrodite Parent genotype Male Parent genotype X Male gametes Female gametes F1 Progeny genotype and ratios F1 Progeny phenotypes Linkage 1: Cross with Unlinked unc +/+ ; unc/unc

Linkage 2: Selfing of hermaphrodite from unlinked cross hermaphrodite Xself cross gametes Progeny genotype Progeny phenotypes and ratios

Hermaphrodite Parent genotype Male Parent genotype X Male gametes Female gametes Progeny genotype Progeny phenotypes and ratios Linkage 1: Crossing with Linked unc Which progeny are you continuing with? Why? + unc/ + unc

Linkage 2: Selfing of hermaphrodite from linked cross hermaphrodite Xself cross gametes Progeny genotype Progeny phenotypes and ratios