What are the major types of chromosomes?

There are four major types of chromosomes based on the position of the centromere. 

Metacentric Chromosomes

In metacentric chromosomes the centromere is located exactly in the center such that both sections are equal in length. Human chromosomes 1, 3, 16, 19, and 20 are metacentric.

Submetacentric Chromosomes

In submetacentric chromosomes, the centromere is slightly offset from the center, resulting in the two sections being of slightly different lengths. Human chromosomes 4 through 12 are submetacentric.

Acrocentric Chromosomes

In acrocentric chromosomes, the centromere is located a distance away from the center, resulting in two sections of very different lengths – one is very long and the other is very short. Human chromosomes 13, 15, 21, and 22 are acrocentric.

Telocentric Chromosomes

In telocentric chromosomes, the centromere is located at the very end of the chromosome, resulting in a V- shape with two equal arms. They are found in a few species such as mice but are absent in humans.