Vegetative cells of the reinhardtii species are haploid with 17 small chromosomes.

The smaller chromosome seems to contain many of the genetic elements that make the cholera organism pathogenic.

The BAC's covering the two smallest human chromosomes, numbers 21 and 22, are essentially complete.

So I chose the smallest chromosome to study, Chromosome 21.

A small extra chromosome is made up of genetic material from chromosome 22 that has been abnormally duplicated (copied).

The smallest chromosome in humans is normally chromosome 21, which is 47 Mb.

A small extra chromosome is found, made up of the top half of chromosome 22 and a portion of the q arm at the q11.2 break.

Plasmids and plasmid-like small chromosomes are, as in eukaryotes, very variable in copy number.

The haploid (base chromosome number) is 20 for nearly every species sampled, but some species have very small chromosomes, making an accurate count difficult.

The X-chromosome is a large, and the Y-chromosome a small telocentric chromosome.