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+--- Thread: Research A new wrinkle in turtles: Their genomes fold in a unique way (/thread-16808.html)
A new wrinkle in turtles: Their genomes fold in a unique way - C C - Nov 12, 2024
https://www.eurekalert.org/news-releases/1064443
INTRO: In their long strings of nucleotides, DNA molecules hold massive troves of genetic data providing instructions for how living organisms should function – the blueprint of life. How the blueprint is stored, however, impacts how it is read and used.
As cells divide and replicate, DNA strands coiled around proteins – chromatin – are in tightly bundled chromosomes. After division, the chromosomes loosen and chromatin is less compact. How and where the chromatin fiber folds and loops onto itself affects what genes are activated. Findings from an Iowa State University-led research team offer new insight into this process that may have potential biomedical uses.
“The three-dimensional structure of the chromatin when it’s folded matters for gene regulation. Where chromatin physically sits in the nucleus matters. The evolution of chromatin folding patterns alters genome function and developmental programs that drive phenotypic evolution and adaptation to changing environments,” said Nicole Valenzuela, professor of ecology, evolution and organismal biology at Iowa State University. “Chromosome folding remains a bit of a black box. We’ve learned a lot about it, but it’s still just the tip of the iceberg.”
The shape and location of chromosomes during the post-division interphase of the cell cycle impacts gene function because it brings non-adjacent regions into contact, such as enhancer sequences and gene promoters. DNA readily available for interaction within active chromatin regions is more likely to be expressed, whereas DNA within less accessible repressed chromatin is silenced.
By analyzing how often different parts of DNA molecules contact each other, scientists have modeled the varying physical configurations of the chromatin in humans and many commonly researched animals, including mice and birds. Add turtles to the list, thanks to a research team Valenzuela helped lead. In a recent paper in Genome Research, the researchers described their study of the genomes of two species of turtles, which showed a surprising chromatin arrangement that hasn’t been observed in other organisms... (MORE - details, no ads)