noun
X chromosome
Genetics term; one of the two sex chromosomes in many organisms.
ヒトの女性は通常二本のX染色体を持つ。
Human females typically have two X chromosomes.
The Y chromosome is the other sex chromosome; males typically have one X and one Y.
From English 'X chromosome', with 染色体 (chromosome) being a Japanese coinage from 染色 (staining) and 体 (body).