All Ychromosomes in existence today are descended from a single ancestor's who is thought to have lived about 140,000 years ago.
现在存在的所有 Y 染色体都来自于一个被认为生活在大约14万年前的同一祖先。
2
There are two chromosomes (chromosome X and chromosome y) involved in this process, and a combination of these chromosomes will determine the gender of the baby.
有两条染色体(染色体x和染色体y)参与到这个过程中，这些染色体的组合将会决定婴儿的性别。
3
However, in 2000, scientists announced that the X and Ychromosomes were once a pair of identical twins.