2026-04-17T03:51:10Zhttps://recercat.cat/oai/request
oai:recercat.cat:2072/4888152025-11-09T13:01:07Zcom_2072_98col_2072_378192
RECERCAT author Marín Gual, Laia author Hogg, Carolyn J. author Chang, J. King author Pask, Andrew J. author Renfree, Marilyn B. author Waters, Paul D. author Ruiz-Herrera Moreno, Aurora 2025-11-09T13:01:07Z 2025-11-09T13:01:07Z 2025 http://hdl.handle.net/2072/488815 Understanding the origin and fate of sex chromosomes has been one of the most intriguing questions in biology. In therian (marsupial and eutherian) mammals, most species are characterized by a heteromorphic XX female XY male sex chromosome system. It is commonly accepted that they originated from a pair of autosomes after gaining a sex-determining function, leading to recombination suppression and subsequent Y chromosome degeneration. Unlike eutherian sex chromosomes which share a pseudo-autosomal region (PAR), the marsupial sex chromosomes are typically tiny and lack any homology. However, there is a lack of empirical evidence on biological systems that represent early stages of sex chromosome differentiation. Here, we describe the meiotic dynamics of an XY1Y2 system in the greater bilby (Macrotis lagotis: family Thylacomyidae) that resulted from a fusion between an autosome and the ancestral X chromosome. We compared the similarities and differences in the regulation of meiosis in two other Australian marsupial species with different sex chromosome systems: the tammar wallaby (Macropus eugenii: family Macropodidae) and the fat-tailed dunnart (Sminthopsis crassicaudata: family Dasyuridae), both with the ancestral XY system. We performed a cytological analysis of meiotic prophase I, including the study of chromosome synapsis, double strand break formation (as a proxy of recombination) and meiotic sex chromosome inactivation. Our results suggest that the neo-PAR in the greater bilby represents an early stage of differentiation, providing new insights into sex chromosome evolution. open access Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original. https://creativecommons.org/licenses/by/4.0/ Marsupials Meiosis Neo sex-chromosomes inactivation Meiotic sex chromosome Double strand breaks Recombination Meiotic dynamics in a unique Australian marsupial provide new insights into the evolution of neo-sex chromosomes in the early stages of differentiation Article