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[Chapter 3-4] A cross was carried out between the following two pureline parental strains:Parent 1: A/A; b/b; D/D; e/e; F/FParent 2: a/a; B/B; d/d; E/E; f/fAll genes are sorted independently except for E and F, which are tightly linked with no crossover between them. Following the selfing of the F1 from the cross between the two parental strains, what proportion of the F2 individuals will phenotypically resemble either one of the two parental lines? (1 pt

User Deikyb
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Answer:

Following the selfing of the F1 from the cross between the two parental strains, what proportion of the F2 individuals will phenotypically resemble either one of the two parental lines?

= 7.03% of F2 progeny will resemble parent 1

= 2.34% of F2 progeny will resemble parent 2.

Step-by-step explanation:

Parent 1: AA; b/b; D/D; e/e; F/F

Parent 2: a/a; B/B; d/d; E/E; f/f

F1 Progeny: A/a; B/b; D/d; E/e; F/f

knowing that the F1 progeny is selfed, the possible gamete outcomes are:

ABDeF , ABDEf, ABdeF, ABdEf

AbDeF , AbDEf , AbdeF , AbdEf

aBDeF , aBDEf , aBdeF , aBdEf

abDeF , abDEf , abdeF , abdEf

All gametes are either eF or Ef (the two parental genotypes) and never EF or ef.

At the A, B and D loci, the F1 are heterozygotes. Therefore, in the F2 progeny, for each locus, 3/4 of the progeny will have the dominant trait while 1/4 will have the recessive phenotype. Further, 1/2 of all F2 progeny will have the haplotype eF and the other half will be Ef.

Proportion of progeny resembling Parent 1:

Parent 1 has the Phenoytpe AbDeF. As previously discussed, 3/4th of all F2 progeny has the phenotype A, 1/4th of F2 progeny has the phenotype b, 3/4th of F2 progeny has the phenotype D and 1/2 of F progeny has the phenotype eF.

Thus, the proportion of progeny resembling Parent 1

= 3/4 x 1/4 x 3/4 x 1/2 = 0.0703125

= 7.03% of F2 progeny will resemble parent 1.

Proportion of progeny resembling Parent 2:

Parent 2 has the Phenoytpe aBdEf. As previously discussed, 1/4th of all F2 progeny has the phenotype a, 3/4th of F2 progeny has the phenotype B, 1/4th of F2 progeny has the phenotype d and 1/2 of F progeny has the phenotype Ef.

Thus, Proportion of progeny resembling parent 2

= 1/4 x 3/4 x 1/4 x 1/2 = 0.0234375

= 2.34% of F2 progeny will resemble parent 2.

User Rubens Farias
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