Heterochromatin
From ISOGG Wiki
Heterochromatin is "a chromosomal region that remains highly condensed throughout the cell cycle and shows little or no evidence of active gene expression".[1]
Heterochromatin contains very long repetitive sequences, and is very difficult to sequence with current technology. About half of the Y chromosome is made up of heterochromatin and has not yet been sequenced. The p arms of chromosomes 13, 14, 15, 21, and 22 contain heterochromatin and have also not been sequenced. There are also large regions of heterochromatin near the centromeres of chromosomes 1 and 9. See the NCBI Genetics Review website for a diagram showing the regions of the human genome where there are large portions that are heterochromatin.
References
- ↑ Strachan, T. and Read, A.P. 1999. Glossary in Human Molecular Genetics, 2nd ed. New York: John Wiley & Sons. Cited by the NBCI Genetics Review.