Animal Breeding and Genetics Specialization: Review on Mechanisms of X-chromosome inactivation in different mammals (Published)
Sex chromosomes differ significantly in their gene content (Adler et al., 1997), which has led to the evolution of mechanisms of dosage compensation (LYON, 1962; Mary F. Lyon, 1961). At least three different mechanisms have been described to adjust sex chromosome gene expression dosage between males and females. The single male X-chromosome is hyper transcribed in flies; both X-chromosomes are partially repressed in worms, while in mammals one of the two X-chromosomes is silenced in each cell (Mary F. Lyon, 1961). In mammals, dosage compensation for X-linked gene products between the sexes is achieved by X-chromosome inactivation (XCI) in females (Mary F. Lyon, 1961). This process leads to the highly regulated transcriptional silencing of one of the two X-chromosome during early development, leading to the formation of the heterochromatic Barr body.
Keywords: animal breeding, different mammals, genetics specialization, mechanisms of X-chromosome