Question

The following statements apply to concepts and material discussed in Chapter 13; identify which statement is TRUE.

Answers:	Chromosomal abnormalities always affect phenotypes.
	Karyotypes are useful tools in diagnosing genetic disorders because they reveal the exact DNA sequence present.
	Most cases of Trisomy involve an extra copy of a sex chromosome.
	Most individuals with aneuploidy have an extra autosome.
	Translocations occur when homologous chromosomes swap genes.

Answer 1

Inversions and translocations are a type of chromosomal abnormalities which do not affect phenotypes.

Karyotypes do not reveal DNA sequence, they are arranged according to size, used in genetic disorder diagnosis

Most Trisomy cases are autosomal.

Translocations occur by swapping genes between non-homologous chromosomes

The correct option is (4) because, The most frequent aneuploidy in humans is Trisomy 16,where the infants do not survive with full version of this chromosomal abnormality. The common aneuploidy that infants survive is trisomy 21 i.e. Down syndrome affecting 1in 800 followed by Edward's syndrome(trisomy 18)an Patau Syndrome(trisomy 13).