Scholars from the Universitat Autònoma de Barcelona (UAB) and the University of Kent recently conducted a study that tackles how the genomes evolve in male germ cells. The research was carried out through the three-dimensional structures of the sperm cells through a series of imaging.
Genomes and Sperm Cells: Identification of Separate Species
The study was made possible through the help of rodent subjects. According to the authors, the focus of the investigation is to get ahold of the details of the distinctive changes that happen in the cellular sperm and egg cell reproduction, and how each of these shifts influences the genome evolution.
Based on the findings, the differences across the mammalian genome pool that the authors examined reveal various orders could be reconstructed based on species. The arrangements alone could also drive the gene function and regulation, and these factors eventually push the evolutionary changes in the identity of a particular species.
The gene arrangements, however, remained a mystery until today. The specifications as to how the developments take place and what cells are responsible for these transitions were not identified in the past.
Through the collaboration of experts from the Universitat Autònoma de Barcelona (UAB) and the University of Kent, it was shown that sperm production is among the key factors to arrange and organize parts of the genome, as well as in making distinctions between species under the same order.
Inherited chromosomal rearrangements, according to the authors, are heavily tied with the biochemical and physical processes that occur during the final phase of sperm reproduction, just right after the completion of meiotic cell division.
Chromosomes Kept and Passed Through Last Stage of Sperm Cell Development
UAB Institute of Biotechnology and Biomedicine's cellular biology, physiology, and immunology specialist Aurora Ruiz-Herrera, who also served as the lead author of the study, explained in a SciTechDaily report that the chromatin remodeling they examined over the formation of male gametes revealed the fundamental information about the genomes near the nucleus.
These changes are possibly involved in the arrangements of the chromosome, as well as in the various phases involved during male spermatogenesis, Ruiz-Herrera added.
The investigation was carried out over 13 various rodent species, each of which had genetic arrangements that identified their groups unscrambled.
University of Kent's School of Biosciences genomics specialist and co-author of the study Marta Farre explained that, through this approach, they have determined the exact locations of the evolutionary breakpoint regions or EBRs that are linked to genome arrangements and identify the common genetic ancestors of the rodent subjects.
The EBRs were evidently associated with the active regions during the final phases of spermatogenesis, the stage in which the developing male germ cells are still considered spermatids.
Kent's molecular genetics and reproduction expert Peter Ellis, who also co-authored the study, said that these EBRs break and region stretches of DNA inside the spermatid nucleus and are physically close to each other.
These arrangements are what separates each rodent species and serve as identifications between squirrels, rats, and rabbits, Ellis continued.
In conclusion, the sperm cells were found to keep and pass a 'memory' of the past genetic configurations, and these stretches of DNA are initially intact in developing sperm cells but are later distributed across various chromosomes in a rodent species.
The study was published in the journal Nature, titled "3D chromatin remodelling in the germ line modulates genome evolutionary plasticity."
RELATED ARTICLE : Fluffy Herding Dogs in South America Found as Closest Relative of UK Ancient Sheepdog Breed from 200 Years Ago
Check out more news and information on Biology in Science Times.
