A cross was made between individuals of genotypes CC DD and cc dd. The F1 genera
ID: 193286 • Letter: A
Question
A cross was made between individuals of genotypes CC DD and cc dd. The F1 generation was test-crossed to the cc dd parent. The offspring were:
Cc Dd 903
cc dd 897
Cc dd 98
cc Dd 102
C and D are linked genes.
How far apart are these loci in map units? Show your work.
The following cross was conducted: CC dd x cc DD. What is the allele arrangement in the F1 (cis or trans)?
The F1 generation from 4.B were testcrossed. What genotypes and genotypic proportions would you expect in the F2 generation? Indicate the nonrecombinant and recombinant progeny.
Explanation / Answer
Answer.
A). CCDD x ccdd----parents
CD/cd-----------F1
CD/cd. X. cd/cd-----------F1 cross
Recombinant genotypes, Ccdd and ccDd = 98+102= 200
Non-recombinant progeny, CcDd and ccdd= 903+897= 1800
Total progeny= 2000
Recombination frequency= (recombinant progeny/ total progeny)100
= (200/2000)100
=10%
Recombination frequency= distance between the genes
The two genes are 10 map units far away.
4b).
CC/dd. X. cc/DD------parents
Cd/cD---------f1 ( trans arrangement)
4c).
Cd/cD. X cd/cd. -----Test cross
cd Cd Cd/cd----25%(non-recombinant) cD cD/cd----25%(non-recombinant) CD CD/cd----25%(recombinant) cd cd/cd----25%(recombinant)Related Questions
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