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Inheritance pattern in chromosomal abnormalities

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1. In a diploid organism of 2n = 10, assume that you can label all the centromeres derived from its female parent and all the centromeres derived from its male parent. When this organism produces gametes, how many male- and female-labeled centromere combinations are possible in the gametes?

2. Human cells normally have 46 chromosomes. For each of the following stages, state the number of nuclear DNA molecules present in a human cell:

a. Metaphase of mitosis
b. Metaphase I of meiosis
c. Telophase of mitosis
d. Telophase I of meiosis
e. Telophase II of meiosis

3. Suppose you discover two interesting rare cytological abnormalities in the karyotype of a human male. There is an extra piece (or satellite) on one of the chromosomes of pair 4, and there is an abnormal patter of staining on one of the chromosomes of pair 7. Assuming that all the gametes of this male are equally viable, what proportion of his children will have the same karyotype as his?

4. Suppose that meiosis occurs in the transient diploid stage of the cycle of a haploid organism of chromosome number n. What is the probability that an individual haploid cell resulting from the meiotic division will have a complete parental set of centromeres (that is, a set all from one parent or all from the other parent)?

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Solution Summary

Crossing over occurs in 4 strand stage. Out of the four chromatids only two participate in crossing over and the remaining two remains unchanged. Hence, 50 % of the individual will be like parents and rest of the 50 % will be recombinants

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