<P> A Barr body ( named after discoverer Murray Barr ) is the inactive X chromosome in a female somatic cell , rendered inactive in a process called lyonization , in those species in which sex is determined by the presence of the Y ( including humans ) or W chromosome rather than the diploidy of the X . The Lyon hypothesis states that in cells with multiple X chromosomes , all but one are inactivated during mammalian embryogenesis . This happens early in embryonic development at random in mammals , except in marsupials and in some extra-embryonic tissues of some placental mammals , in which the father 's X chromosome is always deactivated . </P>
<P> A Barr body ( named after discoverer Murray Barr ) is the inactive X chromosome in a female somatic cell , rendered inactive in a process called lyonization , in those species in which sex is determined by the presence of the Y ( including humans ) or W chromosome rather than the diploidy of the X . The Lyon hypothesis states that in cells with multiple X chromosomes , all but one are inactivated during mammalian embryogenesis . This happens early in embryonic development at random in mammals , except in marsupials and in some extra-embryonic tissues of some placental mammals , in which the father 's X chromosome is always deactivated . </P>
a barr body in a mammalian female cell represents
a barr body in a mammalian female cell represents
the inactive X chromosome in a female somatic cell
the inactive X chromosome in a female somatic cell