Answer to Question #205990 in Genetics for Thulani Ngwenya

Question

a. A primary spermatocyte has the genotype AaBbee. The A and B loci are linked in cis configuration on the long arm of an acrocentric chromosome. The E locus is on a metacentric chromosome. Show the chromosomes containing these genes at metaphase I telophase I and telophase ii using diagrams. Diagrams must clearly labelled

B. Using information in a) show the resulting telophase I and telophase ii diagrams after a crossover between the A and B locus has occured at Pachytene of meiosis. Diagrams must be clearly labelled

Answer 1

Triple X syndrome which is also called trisomy X or 47,XXX is a rare genetic disorder which is prevalent in females.

Presence of extra X chromosome results from random, sporadic errors during normal division of reproductive cells, that is non disjunction of meiosis.

It is not an inherited disorder.

Normally there is one pair of XX chromosomes in females and XY chromosomes ( sex chromosome) 23rd pair in males.

There is an additional X chromosome in females that results in XXX genotype and 47,XXX karyotype.

This results in neurodevelopmental, behavioral and learning disabilities in affected females.