NEETZoologyPrinciples of Inheritance and Variation
A female patient presents to a clinic with sterility, rudimentary ovaries, and a lack of other secondary sexual characters. Which of the following statements correctly describes the genetic basis and category of her condition?
Options
- AIt is an allosomal trisomy resulting in a karyotype of 47 chromosomes.
- BIt is caused by the presence of an additional copy of chromosome 21.
- CIt is an example of monosomy caused by the failure of cytokinesis during cell division.
- DIt is an allosomal monosomy resulting from the absence of one X chromosome.
Correct answer
D. It is an allosomal monosomy resulting from the absence of one X chromosome.
Step-by-step solution
The symptoms described (sterility, rudimentary ovaries, and lack of secondary sexual characters) are characteristic of Turner's syndrome. Turner's syndrome is an allosomal aneuploidy caused by the absence of one of the X chromosomes, resulting in a karyotype of 45, X0. This condition is a type of monosomy (loss of a single chromosome). Failure of cytokinesis leads to polyploidy (an increase in a whole set of chromosomes), whereas aneuploidy (like monosomy) is caused by the failure of segregation of chromatids durin