Mammals with multiple X chromosomes undergo random X inacti

Mammals with multiple X chromosomes undergo random X - inactivation in each nucleus early in questionable development. This results in only one X Chromosome being active In each cell, no matter how many X chromosomes are present Which sex chromosome genotypes) would you expect to express Exist RNA? a. XXXX b .XXXY C. XY d XX Select all that apply. It has been suggested that any male determining genes contained on the Y chromosome in humans cannot be located m the limited region that synapses with the X chromosome (the PARs) during meiosis What might be the outcome if such genes were located in this region, i e located in the PAR region? Sea-determining loci on the Y chromosome would be inhibited and no offspring would be produced Sea-determining loci on the Y chromosome would be mutated which causes diseases in the offspring Sea-determining loci on the Y chromosome would be transferred through crossing over to the X Chromosome C Sea-determining loci on the Y chromosome would be affected and hermaphrodite feature would develop s

Solution

Answer:

13. (a), (b) and (d)

XXXX has 3 barr bodies.

XXXY has 2 barr bodies.

XY do not have any barr body.

XX has 1 barr body.

14. (c)

The pseudoautosomal regions (PARs) present on both ends of the Y chromosome share homology with regions on the X chromosome and synapse and recombine with it during meiosis. The presence of such a pairing region is critical to segregation of the X and Y chromosomes during male gametogenesis.

So, if the male determining genes were located in the PAR regions, it would get transferred during crossing over to the X chromosome.