aa a is the allele and represents the two chromatids there are two alleles for a diploid organism a ba b two different genes on the same chromosome aa bb two different genes on different chromosomes designated separate chromosomes ID: 433089
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Slide1
Symbols to Know for Crosses
a/a – a is the allele and / represents the two chromatids – there are two alleles for a diploid organisma b/a b – two different genes on the same chromosomea/a ; b/b – two different genes on different chromosomes ; designated separate chromosomesX – symbolizes mating between two different individualsX - symbolizes a self cross – when the hermaphrodite worms fertilize their own eggs+ is the wild type or non-mutant form of a geneSlide2
Creating a heterozygous male
Hermaphrodite Parent genotypeMale Parent genotype
X
Male gametes
Female gametes
Progeny genotype
Which progeny are you continuing with? Why?
Progeny phenotypes
and ratios
+/+
dpy/
dpySlide3
Hermaphrodite
Parent genotypeMale Parent genotypeX
Male gametes
Female gametes
F1 Progeny genotype
and ratios
F1 Progeny phenotypes
Linkage 1: Cross with Unlinked
unc
+/+ ;
unc/uncSlide4
Linkage 2: Selfing of hermaphrodite from unlinked cross
hermaphroditeX
self cross
gametes
Progeny genotype
Progeny phenotypes
and ratiosSlide5
Hermaphrodite
Parent genotypeMale Parent genotypeX
Male gametes
Female gametes
Progeny genotype
Progeny phenotypes
and ratios
Linkage 1: Crossing with Linked
unc
Which progeny are you continuing with? Why?
+
unc/
+
uncSlide6
Linkage 2: Selfing of hermaphrodite from linked cross
hermaphroditeX
self cross
gametes
Progeny genotype
Progeny phenotypes
and ratios