Question

13. In the Kingdom of Utopia the King's oldest son has blue eyes (B), a strong jaw (S) and dimples (D) all of which segregate as dominant mendelian factors. His 999 wives have brown eyes (b), weak jaws (s) and undimpled cheeks (d) and each of them produces one child for him. The son is delighted to find that just one son of his 999 children has blue eyes, strong jaws and dimples like him, because he has a deep love of genetics and therefore understands this outcome. To help the son explain this outcome to his kind but, not so bright father A) state the phase of the alleles in the son and B) draw the genetic map for these three factors indicating the correct sene order and the genetic distance in centimorgans (CM) using Morgan's mapping function C) Calculate the coefficient of interference for these three genes. (16 points) Frequency Frequency Child's phenotype blue eyes, weak jaw, dimples brown eyes, strong jaw, dimples brown eyes, strong jaw, no dimples brown eyes, weak jaw, dimples 255 34 201 Child's phenotype Child's phenotype blue eyes, strong jaw, dimples blue eyes, strong jaw, no dimples blue eyes, weak jaw, no dimples brown eyes, weak jaw, no dimples 193 270 5

Answer 1

a) Phase of allele in the son - BbSsDd

Because father of the son is BbSsDd/ BBSSDD and the wives are bbssdd

b) BSD - 1 - parent

bsd - 5 - parent

BsD - 40 - double crossing over

bSd - 34 - double crossing over

bSD - 255 - single crossing over

Bsd - 270 - single crossing over

bsD - 201 - single crossing over

BSd - 193 - single crossing over  

Distance between B - S = (number of recombinants for gene B -S ) * 100 / ( total number of progenies)

= (255+270+40+34) * 100 / 999

= 60 cM

Distance between B- D = (201+193+255+270) * 100/ 999

= 92 cM

Distance between S - D = (201+193+40+34) * 100/ 999

= 46.84 cM

Distance between b- s = (255+270+40+34) * 100/ 999

= 60 cM

Distance between b- d = (193+201+270+255) * 100/ 999

= 92 cM

Distance between s - d = (201+193+40+34) * 100 / 999

= 46.84 cM

Gene diagram

90CM B- S 60CM . 460M b* bom s A60MED * approximately