A recessive mutant allele_ vermillion_ causes bright orange eyes in

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A recessive mutant allele_ vermillion_ causes bright orange eyes in Powered By Docstoc
					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
vermillion? Why?
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:
                                 Checkered Plain
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
                                 Checkered Plain
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

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