Dr. Ruth Ballard Page 1 11/28/20
BIO 184 Fall 2006
NAME____________________________________________LAB SEC#_____
HOMEWORK 3
(due 12/14/06)
Please write all your final answers in the space provided below each question.
1. (12 points)
Among tribbles (an alien species indigenous to Star Trek), the ability to emit a high pitched
purring sound is under the control of a single gene. Similarly, the abilities to utilize triticale
grain as an energy source and to produce large litter sizes are also controlled by single
genes.
P = purring T = can utilize triticale L = large
litter sizes
P = cannot purr t = cannot utilize tritacle l = small litter
sizes
A female tribble with the genotype (Pp,Tt,Ll) is crossed to a non-purring male who cannot
utilize triticale and is homozygous for the allele that causes small litter sizes. From this
mating, the following offspring are produced:
567 PTl
600 ptL
22 PTL
18 ptl
2 PtL
0 pTl
103 pTL
98 Ptl
a. Which gene is in the middle? How do you know?
b. Calculate the map distance between adjacent genes. Show all your work.
c. Draw a map of the three genes, indicating the distance between adjacent genes,
which gene is in the middle, and the total distance between the two outside genes.
