An Individual's Karyotype Shows Trisomy 21

Question

An individual's karyotype shows trisomy 21. This is an example of a
A) translocation.
B) chromosomal abnormality.
C) mutation.
D) recombination error.
E) teratogen.

Accepted Answer

Trisomy 21 is an example of a chromosomal abnormality where there is a third copy of chromosome 21. This occurs during meiosis and can result in Down syndrome. Translocations, mutations, recombination errors, and teratogens can all cause genetic abnormalities, but do not specifically refer to a third copy of a chromosome.