In the past Y chromosome was thought to be an empty gene which is now proven not true. It contains fewer genes compared to X chromosomes. Y chromosome are split into three parts pseudoautosomal (PAR) regions sharing the same ancestry regions on the X chromosome when is recombined in the process of meiosis and the male-specific regions of the Y (MSY) which also has some genes not all share the same ancestry with the X chromosome. Then the male specific region of the Y are then further divided into three parts which one contains functional genes (euchromatic region), the other contains lacking genes (heterochromatic region) and sex-determining region Y (SRY) are the testis-determining factor.
- ↑ William S.Klug Michael R. Cummings Charlotte Spencer Michael Palladino (2010). concepts of genetics. 10th ed. United Kingdom: Pearson. p224-225.