A threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.‘Ring chromosomes, chromatid exchanges and polyploidies were also observed at some treatments.’
- ‘The sizes of the two centromeres from the homologous chromosomes are different.’
- ‘The sex chromosomes are placed to the right of the smallest autosomal chromosomes.’
- ‘Our genes are located on 46 paired structures, or chromosomes, in the cell nucleus.’
- ‘So a genetic map is an abstract entity that tells you the relative positions of genes on chromosomes.’
Each chromosome consists of a DNA double helix bearing a linear sequence of genes, coiled and recoiled around aggregated proteins (histones). Their number varies from species to species: humans have 22 pairs plus the two sex chromosomes (two X chromosomes in females, one X and one Y in males). During cell division each DNA strand is duplicated, and the chromosomes condense to become visible as distinct pairs of chromatids joined at the centromere
Late 19th century coined in German from Greek khrōma ‘colour’ + sōma ‘body’.