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Q38 - Inferring Chromosomal Rearrangements from Post-Fertilization Embryo Loss

Theoretical A Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license

A mutated male mouse that is phenotypically normal shows reproductive anomalies when compared with a normal male in terms of mean number of embryos, as shown in Table Q.38. The anomaly manifests itself after fertilization.

Mean number of embryos

Mating Implanted in uterine wall Degeneration after implantation Normal Degeneration (%)
mutated ♂ x normal ♀ 8.7 5.0 3.7 57.5
normal ♂ x normal ♀ 9.5 0.6 8.9 6.5

Using the information and data, determine which of the statements are true or which are false.

A. The mutated male mouse can have a chromosome deletion.
B. The mutated male mouse can be a chromosomal translocation heterozygote.
C. The mutated male mouse can be a chromosomal inversion heterozygote.
D. The genetic defect in mutated male could be verified by cytological observation of meiotic cells in the mouse.

Question reproduced from IBO 2016, Theoretical Paper A, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)