• species
  • This suggests that the W chromosome is essential in female determination in some species (ZZW), but not in others (Z0). (wikipedia.org)
  • Y is the sex-determining chromosome in many species, since it is the presence or absence of Y that determines the male or female sex of offspring produced in sexual reproduction. (wikipedia.org)
  • Hypermethylation of microchromosomes compared to macrochromosomes is a shared feature between P. vitticeps and avian species. (biomedcentral.com)
  • Cross-species chromosome painting and gene mapping amongst avian species demonstrate, in most cases, that a microchromosome in one species is conserved as a microchromosome in another [ 4 - 7 ], indicating that microchromosomes are fairly conserved amongst aves. (biomedcentral.com)
  • Moreover, it is a proposed regulatory mechanism for several species, whose study has so far been limited or led to inconclusive data as to the attempt to detect a single, specific, sex-determining gene. (biomedcentral.com)
  • Building on work done by Ohno and his colleagues, Lyon eventually proved that either the maternal or paternal X chromosome is randomly inactivated in every cell of the female body in the species she was studying, which explained the heterogeneous fur patterns she observed in her mosaic mice. (wikipedia.org)
  • sperm
  • The platypus has a ten-chromosome-based system, where the chromosomes form a multivalent chain in male meiosis, segregating into XXXXX-sperm and YYYYY-sperm, with XY-equivalent chromosomes at one end of this chain and the ZW-equivalent chromosomes at the other end. (wikipedia.org)
  • Sex comprises the arrangements that enable sexual reproduction, and has evolved alongside the reproduction system, starting with similar gametes (isogamy) and progressing to systems that have different gamete types, such as those involving a large female gamete (ovum) and a small male gamete (sperm). (wikipedia.org)
  • differences
  • The conservation of this division between macro- and microchromosomes over a long evolutionary timescale makes it interesting to characterize the similarities and differences between the two types of chromosomes, including the distribution of epigenetic marks. (biomedcentral.com)
  • Attention is paid to their length, the position of the centromeres, banding pattern, any differences between the sex chromosomes, and any other physical characteristics. (wikipedia.org)
  • evolution
  • The reason for the evolution of sex, and the reason(s) it has survived to the present, are still matters of debate. (wikipedia.org)
  • female
  • On November 3, 2010, scientists announced the discovery of a female Boa constrictor that can produce offspring without mating and, through such asexual reproduction, produced 22 female offspring, all with a WW chromosome genetic makeup. (wikipedia.org)
  • However, because of their WW chromosomes, any offspring they produce will be female. (wikipedia.org)
  • Then, in 1959 Susumu Ohno proved that these satellite-like structures found exclusively in female cells were actually derived from female X chromosomes. (wikipedia.org)
  • Long-suspected connection between female sex hormones and development of cancer identified for the first time. (cshlpress.com)
  • process
  • One of the basic properties of life is reproduction, the capacity to generate new individuals, and sex is an aspect of this process. (wikipedia.org)
  • central
  • To determine whether this is likely to be a common feature of amniote microchromosomes, we have analysed the distribution of epigenetic marks using immunofluorescence on metaphase chromosomes of the central bearded dragon ( Pogona vitticeps ). (biomedcentral.com)
  • whose
  • Simultaneously, Mary F. Lyon began investigating manipulations of X-linked traits that had phenotypically visible consequences, particularly in mice, whose fur color is a trait intimately linked to the X chromosome. (wikipedia.org)