Male and female genomes also differ about most other sex chromosome, the brand new X chromosome, in this women has actually double the fresh new dose out of X-chromosomelinked genes you to men keeps. The fresh X chromosome consists of as much as 160 mil legs sets off DNA (regarding 5 percent of complete haploid genome) and you may encodes an estimated 1,000 in order to 2,000 family genes (Shape dos–2). Because of the characteristics off X-chromosome-linked designs from heredity, women can be often homozygous otherwise heterozygous to possess X-chromosome-linked attributes, whereas guys, as they only have just one X-chromosome, was hemizygous. Ones X-chromosome-connected family genes proven to day, some are X-chromosome certain; simply pseudoautosomal genetics and a few genes you to definitely map beyond this new pseudoautosomal region was basically demonstrated to has actually functionally equivalent Y-chromosome homologues (Willard, 2000).