The female sex chromosome. This chromosome occurs as a pair in each female cell (ie XX), and unpaired in each male cell (ie XY).
Xenotransplantation
The transplantation of tissue from one species to another species, typically from non-human mammals to humans. This technology has become very important because of a worldwide shortage of human organs for humans requiring a new organ. The most popular non-human species involved in this technology is the pig.
