The following pedigree describes the distribution in a family of hemophilia and
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Question
The following pedigree describes the distribution in a family of hemophilia and red-green colour blindness. Hemophiliacs are indicated by shading of the upper portion of the symbol, HemophillaColor BI 3 1 23456 7 8 9 10 1 12 a. Are colour blindness and hemophilia dominant or recessive traits2 State your reasoning. c. From the individuals in generation III, which are recombinants for hemophilia and colour. blindness genes d. Using individuals IIIl through III,9 only, calculate the recombination frequency between the colour blindness and hemophilia genes. Which individual should you exclude from this calculation, and why?Explanation / Answer
3.a) The red-green color blindness and hemophilia are purely a sex linked recessive traits. This means that the disorder is linked in the X chromosome. Females have two X chromosomes while male have one X chromosome and one Y chromosome. The expression in male and females is not the same. So we can say that genes on the X chromosome can be recessive or dominant both.
b) The color blindness and hemophilia are both X chromosome linked which means that the defect lies in the X chromosome. Male have one X and one Y chromosome whereas famales have 2 X chromosome.
c) From the individuals in generation III, the recombinants for the color blindness and hemophilia are 1,3,5,7 and 9.
d) Recombination frequency = (Number of Recombinant Progeny/Total Number of progeny)*100
= (5/9)*100= 55.55
4 and 6 are excluded because they are not recombinant progeny
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