• The Lyon hypothesis also accounted for the findings that one copy of the X chromosome in female cells was highly condensed, and that mice with only one copy of the X chromosome developed as infertile females. (wikipedia.org)
  • During metaphase the X-shaped structure is called a metaphase chromosome, which is highly condensed and thus easiest to distinguish and study. (wikipedia.org)
  • This suggested to Ernest Beutler, studying heterozygous females for glucose-6-phosphate dehydrogenase (G6PD) deficiency, that there were two red cell populations of erythrocytes in such heterozygotes: deficient cells and normal cells, depending on whether the inactivated X chromosome (in the nucleus of the red cell's precursor cell) contains the normal or defective G6PD allele. (wikipedia.org)
  • It is known that in the inner cell mass (the embryo proper) of mice, XCI occurs randomly, while in the extra-embryonic tissues, imprinted XCI deterministically inactivates the paternal X. In early mouse embryos, the paternal X chromosome is already partially silenced at the zygote stage by imprinted XCI, suggesting that sex-chromosome dosage compensation exists from conception. (wikipedia.org)
  • In his famous textbook The Cell in Development and Heredity , Wilson linked together the independent work of Boveri and Sutton (both around 1902) by naming the chromosome theory of inheritance the Boveri-Sutton chromosome theory (the names are sometimes reversed). (wikipedia.org)
  • Write the names of primary sex organs found in male and female human beings. (rbsesolutions.com)
  • Primary sex organs are a pair of testes or male gonads. (rbsesolutions.com)
  • It is known that in the inner cell mass (the embryo proper) of mice, XCI occurs randomly, while in the extra-embryonic tissues, imprinted XCI deterministically inactivates the paternal X. In early mouse embryos, the paternal X chromosome is already partially silenced at the zygote stage by imprinted XCI, suggesting that sex-chromosome dosage compensation exists from conception. (wikipedia.org)
  • A gamete is the mature reproductive or sex cell that contains a haploid number of chromosomes (i.e., 50% of the genetic material or only one set of dissimilar chromosomes) and is capable of fusing with another haploid reproductive cell to form a diploid zygote. (biologyonline.com)
  • a mature haploid reproductive cell as produced by gametogenesis , and that which fuses with another from the opposite sex at fertilization resulting in the formation of a zygote that develops into a new individual. (biologyonline.com)
  • In humans, each gamete contains 23 chromosomes and their fusion results in the formation of a diploid zygote containing 46 chromosomes . (biologyonline.com)
  • Take up association with primordial sex Sex The totality of characteristics of reproductive structure, functions, phenotype, and genotype, differentiating the male from the female organism. (lecturio.com)
  • The Lyon hypothesis also accounted for the findings that one copy of the X chromosome in female cells was highly condensed, and that mice with only one copy of the X chromosome developed as infertile females. (wikipedia.org)
  • This suggested to Ernest Beutler, studying heterozygous females for glucose-6-phosphate dehydrogenase (G6PD) deficiency, that there were two red cell populations of erythrocytes in such heterozygotes: deficient cells and normal cells, depending on whether the inactivated X chromosome (in the nucleus of the red cell's precursor cell) contains the normal or defective G6PD allele. (wikipedia.org)
  • In 1961, Mary Lyon proposed the random inactivation of one female X chromosome to explain the mottled phenotype of female mice heterozygous for coat color genes. (wikipedia.org)
  • However, the phases of gametogenesis are similar, with germ cells progressing through mitosis Mitosis A type of cell nucleus division by means of which the two daughter nuclei normally receive identical complements of the number of chromosomes of the somatic cells of the species. (lecturio.com)
  • Mitosis Mitosis A type of cell nucleus division by means of which the two daughter nuclei normally receive identical complements of the number of chromosomes of the somatic cells of the species. (lecturio.com)
  • In mice, Xi reactivation is known to occur in three developmental stages: In the oocyte after fertilization, the paternal X chromosome is reactivated, reversing male meiotic sex chromosome inactivation (MSCI). (wikipedia.org)
  • X chromosome reactivation (XCR) is the process by which the inactive X chromosome (the Xi) is re-activated in the cells of eutherian female mammals. (wikipedia.org)
  • Therian female mammalian cells have two X chromosomes, while males have only one, requiring X-chromosome inactivation (XCI) for sex-chromosome dosage compensation. (wikipedia.org)
  • This process results in gametes that are haploid Haploid The chromosomal constitution of cells, in which each type of chromosome is represented once. (lecturio.com)