On the Y Chromosome there is the gene SRY, which triggers testis development if present. The human Y chromosome is composed of about 50 million base pairs.
The X Chromosome about 155 million DNA building blocks (base pairs) and represents approximately 5 percent of the total DNA in cells. The gene FLNA is one of 900 - 1,400 genes that are located on the X chromosome. When it is affected digestive disorders can occur .