As part of a large genetic study leading to the molecular identification of muta
ID: 149355 • Letter: A
Question
As part of a large genetic study leading to the molecular identification of mutations that result in dwarfism, a number of families who have dwarf family members were examined. Listed below are the offspring pooled from families in which both parents are dwarfs normal dwarf male female 740 760 260 240 a. Based on the data shown above, what is a possible pattern of inheritance (sex-linked, autosomal recessive, autosomal dominant), and what is the dominant allele? (5 pts) b. Given your model in part a, how many of each type of offspring would you expect (essume the same numbers of males and females as the data) (10 pts)? male female normal dwarf c. Show a calculation you might use to test whether your model agrees with your data. Set up any equations you need, and explain what you will do, and how you will interpret it (5 pts). d. You do the calculation in part c, and find a p-value of 0.004 What does this suggest about your model in part a (5 pts)? e. Does this make sense to you? Are you surprised? Why or why not (5 pts)?Explanation / Answer
a. As it occurs almost euqally in both male and female and is lesser in number as compared to tallness, dwarfness is likely to be autosomal recessive.
The dominant trait may be tallness.
T- tall. t- dwarf
2. We would expect a ratio of 3:1 for both male and female as it is a case of monohybrid cross.
Hence, it would be 750 tall people for 250 dwarf people for both male and female.
3.
Calculating the Chi-square test for the above data, we see that none of the percentages are more than 5%, hence it is due to chance.
ie, there is very less variability.
d. This suggests that the model suggested in part a may be the correct one, as the deviation from expected results is very less.
e. Yes, it makes sense and we are not surprised as we were already expecting close results which are seen here.
Male Observed Expected (O-E)2 (O-E)2/E Tall 740 750 100 0.133 Dwarf 260 250 100 0.4 Total 1000 1000 200 0.533Related Questions
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