chromosome 11

chromosome 11 is one of the 23 pairs of chromosomes in humans. It spans approximately 135 million base pairs and represents about 4 to 4.5 percent of the total DNA in cells. This chromosome contains a diverse array of genes, including many critical for immune function, sensory perception, and cellular metabolism.

Overview

Chromosome 11 is a submetacentric autosome and was one of the first human chromosomes to be fully sequenced by the Human Genome Project. Its sequence, published in a landmark issue of *Nature*, provided crucial insights into genomic organization. The chromosome is notable for its high gene density and contains several large gene clusters, such as the β-globin locus, which is pivotal for oxygen transport. Research on this chromosome has been fundamental to understanding human genetics and has been facilitated by resources from the Wellcome Trust Sanger Institute.

Genes

Chromosome 11 harbors between 1,300 and 1,700 protein-coding genes. Among its most significant clusters are the β-globin gene cluster on the short arm, which includes genes for hemoglobin subunits like HBB, and the RAS oncogene family, including HRAS. It also contains genes for tyrosinase, essential for melanin production, and the brain-derived neurotrophic factor (*BDNF*). Other notable genes include those for the dopamine receptor *DRD4*, the insulin gene *INS*, and the apolipoprotein *APOA1*, studied extensively at institutions like the Broad Institute.

Diseases and disorders

Numerous genetic disorders are linked to mutations on chromosome 11. These include sickle cell disease and beta-thalassemia, caused by defects in the β-globin locus. Wilms tumor, a pediatric kidney cancer, is associated with mutations at the WT1 locus. Beckwith-Wiedemann syndrome, an overgrowth disorder, involves dysregulation of imprinted genes in the 11p15.5 region. Other conditions include hereditary angioedema (linked to *SERPING1*), Meniere's disease, and certain forms of deafness. Research into these disorders is advanced by organizations like the National Institutes of Health and the Howard Hughes Medical Institute.

Cytogenetic banding

The G-banding pattern of chromosome 11 reveals distinct light and dark cytogenetic bands that correlate with gene density and chromatin structure. The short arm (11p) is divided into regions p15, p14, p13, p12, and p11, with p15 containing the aforementioned Beckwith-Wiedemann syndrome critical region. The long arm (11q) includes bands q12 through q25, with the Jacobsen syndrome critical deletion region located at 11q23. These bands are essential for karyotype analysis in clinical diagnostics, such as at the Mayo Clinic, and for mapping chromosomal translocations found in Ewing sarcoma.

Genomic evolution and comparative genomics

Comparative genomic studies reveal that chromosome 11 shares synteny with regions in other mammals, such as mouse chromosome 7 and dog chromosome 22, indicating conserved genomic architecture. The β-globin locus has been a model for studying gene family evolution and gene duplication events. Research led by teams at the European Molecular Biology Laboratory shows that the organization of olfactory receptor genes on this chromosome has undergone significant evolutionary divergence in primates. These studies provide insights into human evolution and are supported by databases like the UCSC Genome Browser.

Category:Human chromosomes