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.
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.
<u>Proportion of progeny resembling Parent 1:
</u>
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.
<u>Proportion of progeny resembling Parent 2</u>:
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.
