Question
Please answer questions
a 4 pts) You have discovered a mew s Nou set Cros marker 2 x Cross 3: mutation dpy-1 progeny for the crosses are allowed to and you select the animals he carrying marker from this cross. You find following res lus Of 300 marker mutation I animals, 200 are dry-1 of 300 arke Of 300 m 2 animals, 150 are dpy-1 mark mutation 3 animals, 15 are dry-1 a) On which chromosome is dpy-17 You now wish to determine the position of dpy-1 on the chromosome. You have identified several other recessive mutations on that These other mutations include cyeless zygous. and hairy. You have a female worm that is lor cyeless, hairy, and dpy-1 and tcstcross the animal Ci.c., mate the het to an animal onnozygous for eyeless, ha dpy-1) Among the looo FI progeny from the testcross, the following phenotyves were observed Dp 1. eycless. hairy Inc O wild type hairy, dpy. 30 eyeless eyeless, hairy Sc dpy. 36 eyeless, dpy-1 airy b) What is the order of genes on the chromosome and the map distances between the genes 2) (12 pts) You were taking the subway to class one day and captured several family me an unknown rodent species on the platform. You gave them to your genetics professor analyze, and she performed the following crosses. The F2 progeny are the result of cr F1 progeny to each other
Explanation / Answer
1) a) The dpy-1 gene must be in chromosome 1 based on the quantitative data.
b) Parental types are represented by the presence of higher number of offsprings. Here, therefore the parental types are dpy-1, eyeless,hairy and wild type. Double recombinants are present in lowest number. Therefore, eyeless, dpy-1 and hairy are recombinants.
Hairy is present as the only trait in one of the double recombinants. So, it must be in the middle. Therefore the gene order is dpy-1, hairy, eyeless.
Distance between dpy-1 and hairy,
= 100 x (30+36+4+6) / 1070
= 100 x 76 / 1070
= 7.10 cM
Distance between hairy and eyeless,
= 100 x (40+34+4+6) / 1070
= 100 x 84 / 1070
= 7.85 cM
The gene map is
dpy-1 hairy eyeless
I------------------------------I--------------------------------------I
7.1 cM 7.85 cM