Biology 111:3 Mendelian Genetics Problems 1. In cats, all white coloration is a
ID: 134315 • Letter: B
Question
Biology 111:3 Mendelian Genetics Problems 1. In cats, all white coloration is a dominant trait over partially white. If two all white cats are mated, what are the possible phenotypic ratios of the offispring? Draw out the Punnett squares to support your answers. 2. The Palomino horse is golden in color. Highly desired in the horse breeding world, this phenotype does not breed true. In a series of matings between palominos (both stallion and mare) the following genotypes were obtained: 65 Palominos 32 Cream (light) 34 Chestnut (dark) What is the probable mode of inheritance of palomino coloration? Explain why you think so. 3. In certain cattle, hair color is a co-dominant trait and can be red (homozygous RR) or White (Homozygous R'R) or Roan (both red and white hair, heterozygous RR) (A) When a red cow is mated with a white bull what genotypes and phenotypes of offspring could be obtained?Explanation / Answer
Answer:
1).
All white = WW or Ww
Partially white = ww
Ww (all white) x Ww (all white)-------------Parents
W
w
W
WW (all white)
Ww (all white)
w
Ww (all white)
ww (partially white)
All white = ¾
Partially white = ¼
The phenotypic ratio = 3:1
2).
The mode of inheritance is incomplete dominance, which involves one gene with two alleles as follows.
DD =Dark
dd= Light
Dd = Palominos
Dd x Dd—Parents
D
d
D
DD (dark)
Dd(palominos)
d
Dd(palominos)
dd (light)
The phenotypic and genotypic ratio is same, i.e., 1:2:1 = Dark : Palominos : Light
3). A).
RR (red) x R’R’ (roan)----Parents
RR’ (roan)------------F1 offspring
B). RR’(roan) x R’R’---Parents
R’
R
RR’ (Roan)
R’
R’R’ (white)
Genotypic ration and phenotypic ratio is same, i.e., 1:1
5). XH Xh (carrier woman) x (normal man) XH Y)---Parents
XH
Y
XH
XH XH (normal daughter)
XH Y (normal son)
Xh
XH Xh (normal daughter)
Xh Y (hemophilic son)
50% of their sons will have the disease
The probability of their first child with hemophilia =1/4 or 25%
W
w
W
WW (all white)
Ww (all white)
w
Ww (all white)
ww (partially white)
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.