If a human female has 2 Barr bodies per cell,it is almost certain that
A)her father had 1 Barr body per cell.
B)her mother also had 2 Barr bodies per cell.
C)she developed from a fertilized egg with 3 X chromosomes.
D)she is genetically a male with female characteristics.
E)she is genetically a normal fertile female.

Question

Quizplus · Accepted Answer

Barr bodies are inactive X chromosomes that have been silenced during embryonic development in female mammals. Normally, each cell of a female mammal should only have one active X chromosome and one inactive X chromosome (Barr body). If a human female has 2 Barr bodies per cell, it means that she has three X chromosomes (XXX), and two of them are inactive. This is known as Triple X syndrome, a rare genetic disorder that affects about 1 in 1,000 females. Therefore, choice C is the best answer. The other options are not correct because they do not explain the presence of two Barr bodies in every cell.

If a Human Female Has 2 Barr Bodies Per Cell,it