A recessive mutant allele, vermillion, causes bright orange eyes in
Drosophila when homozygous. The usual color is red. What happens
when a vermillion female fly is crossed to a red male fly whose father was
Here are data pertaining to red vs brown eye color in Drosophila. Given
the data, what can you say about the mode of inheritance of brown vs. red
(wild type) eye color? What about the genotypes of the sets of parents,
and of the offspring?
offspring: red brown
brown x brown 0 92
red x red 79 0
red x red 64 21
red x brown 100 0
red x brown 54 60
Pigeons may be checkered or plain. In a series of matings, the following
data were obtained:
a) checkered x checkered 36 0
b) checkered x plain 38 0
c) plain x plain 0 35
The F1 were mated with these results (parental cross is indicated in
F1 x F1 Crosses (parentals) F2 Progeny
1) checkered (a) x plain (c) 34 0
2) checkered (b) x plain (c) 17 14
3) checkered (b) x checkered (b) 28 9
4) checkered (a) x checkered (b) 39 0
How are checkered and plain inherited?
Which allele is dominant? What are the parental genotypes?
Determine genotypes of parents and offspring for each cross.
A red swordtail with crescent spot was crossed to true-breeding olive
spotless fish and the following progeny obtained:
15 red spot,13 red spotless,16 olive spot,14 olive spotless
a. What can we conclude about the inheritance; what are the parental
b. Create symbols for alleles, write out parental genotypes
c. Write out genotypes of progeny