What Is Chromosome 15?

Twenty-first century science is opening up the secrets to genetic health, primarily through the study of chromosomes. Chromosomes are containers for DNA, which carries a person's genetic information. There are 26 different chromosomes in the human body, and most people inherit a pair of each --- one from each parent. The autosomes, or all chromosomes except for the two that determine sex, are numbered by size. According to the U.S. National Library of Medicine, Chromosome 15 accounts for more than 3 percent of the DNA in cells and contains between 650 and 1,000 genes.

Genes Relating to Coloring

• Chromosome 15 is changing science's understanding of eye color.

  Some of the genes that are known to relate to skin and eye color reside in Chromosome 15. These genes include EYCL3, which is a brown eye color gene and EYCL2, which determines where the cells that produce melanin are located on the eye. While multiple genes work together to determine eye color, this discovery is exciting because it debunks the theory that eye color is determined by one dominant gene.

Isodicentric Chromosome 15

• According to the Autism Genetics Cooperative, researches believe that one in every 5,000 babies is born with a 47th chromosome that is an inverted duplication of Chromosome 15. This duplication is called Isodicentric Chromosome 15 and is often accompanied by developmental delays and autistic-like behaviours. Autistic children with genetic disorders have been found to have Isodicentric Chromosome 15 more often than any other genetic disorder, and duplication of the genes on the long arm (q) of this chromosome are increasingly being associated with autism.

Acrocentric Issues

• Chromosome 15 is one of the one of the five acrocentric chromosomes. These chromosomes have one arm that is very short, which places the centromere close to one end. When two acrocentric chromosomes fuse, a Robertsonian Translocation is created. If the short end of a woman's Chromosome 15 fuses with Chromosome 21, she has a 10 to 15 percent chance of having a child with Translocation Down's syndrome.

Deletion on Chromosome 15

• Deletion occurs when a chromosome breaks and genetic material is lost. The breakpoint determines the specific genetic malfunction. According to the U.S. National Library of Medicine, about 70 percent of people with Angelman syndrome have a deletion in Chromosome 15, on the maternal side. Prader-Willi Syndrome, which is a genetic cause of obesity in children, is also affected by deletion in Chromosome 15.