The sex chromosome found together with an X chromosome in most normal males.
Once thought to be a genetic wasteland, the Y now is known to contain at least 20 genes, some of them unique to the Y including the male-determining gene and male fitness genes that are active only in the testis and are thought responsible for the formation of sperm. Other genes on the Y have counterparts on the X chromosome, are active in many body tissues and play crucial "housekeeping" roles with the cell.
A number of specific genes have been Y-linked including:
* ASMTY (which stands for acetylserotonin methyltransferase),
* TSPY (testis-specific protein),
* IL3RAY (interleukin-3 receptor),
* SRY (sex-determining region),
* TDF (testis determining factor),
* ZFY (zinc finger protein), PRKY (protein kinase, Y-linked),
* AMGL (amelogenin),
* CSF2RY (granulocyte-macrophage colony-stimulating factor receptor, alpha subunit on the Y chromosome),
* ANT3Y (adenine nucleotide translocator-3 on the Y),
* AZF2 (azoospermia factor 2),
* BPY2 (basic protein on the Y chromosome),
* AZF1 (azoospermia factor 1),
* DAZ (deleted in azoospermia),
* RBM1 (RNA binding motif protein, Y chromosome, family 1, member A1),
* RBM2 (RNA binding motif protein 2) and
* UTY (ubiquitously transcribed TPR gene on Y chromosome).
The Y is a useful chromosome for tracking men because it is transmitted unchanged from father to son. The Y escapes the intergenerational shuffle (recombination) that affects genes on the X chromosome and the remainder of the genome. All men have essentially the same Y chromosome. It is thought that in our small ancestral population some men had no children or only daughters, so that some Y chromosomes disappeared until only one was left. This ubiquitous Y has the same DNA in every man on earth except for the mutation that crops up every millenium and is then inherited by all males descended from that man.
