Genetic problems

Genetic problems

Genetic problems

1. Pure-breeding affable flies are crossed to pure-breeding striped flies. The F1 flies are all
striped. (Both of these genes are autosomal and linked.)
Which trait(s) are dominant?
The F1 females are test-crossed with the following results:
affable 99
striped 101
affable striped 102
wildtype 98
What is the linkage arrangement of the F1 flies (coupling or repulsion)?
What is the phenotype of the test cross males?
What is the map distance between these genes?
What would be the ratio if the F1 males were test-crossed?
2. Diagram the expected progeny in the following cross, where M represents an unknown
dominant mutant:
Genotype Cy M+ ; D males X Cy+ M+ ; D+ females
Cy+ M D+
Cy+ M+ D+
Phenotype?
What would be the outcome if the above males were crossed to females homozygous for
M?
3. m is a recessive unknown autosomal mutant. F1 males of the phenotype curley and
dichaete (from a cross of Cy/Pm; D/Sb X m/m) are backcrossed to m/m females. The
progeny phenotypes are listed below. On which chromosome is m located?
Progeny
Curly Dichaete
Curly "m"
dichaete
"m"
4. m is a recessive unknown autosomal mutant. F1 males of the phenotype Cy D (from a
cross of Cy/Pm; D/Sb X m/m) are backcrossed to m/m females. The progeny
phenotypes are listed below. What chromosome is m located on?
Progeny
Curly Dichaete "m"
Curly Dichaete
Curly "m"
Curly
Dichaete "m"
Dichaete
"m"
wild type