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Structural chromosomal abnormalities causing pregnancy loss.

A female has suffered five consecutive miscarriages.Cytological study of her peripheral blood revealed 46,XX inv(1) (p32 q34) in all her cells and inversion (9) (p12 q12) in 30% of the studied cells. It is likely that the chromosome 1 abnormality is the cause of the woman's recurrent miscarriages.

a) Explain in words the nature of the woman's chromosome 1 abnormality.

b) Find an ideogram of human chromosome 1 and DRAW with key landmarks, the woman's chromosomes 1, paired during oogenesis' first meiotic prophase. LABEL key landmarks.

c) Suppose in 70% of meiosis there is a crossover somewhere in the region between bands p32 and q34. DRAW the gametic chromosomes 1 that would result from meiosis in which a single crossover occurred within band q 1.1.

d) What fraction of the gametes are likely to give rise to normal development, if the chromosome 1 abnormality is the only cause of gametic/zygotic non-viability?

Solution Preview

a) Explain in words the nature of the woman's chromosome 1 abnormality.

The sequence between p32 and q34 on chromosome 1 is inverted.

b) Find an ideogram of human chromosome 1 and DRAW with key landmarks, the woman's chromosomes 1, paired during oogenesis's first meiotic prophase.LABEL key landmarks.

See attached file.

c) Suppose in 70% of ...

Solution Summary

Short paragraph answers with needed diagrams and web references.

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