Useful garbage
The mystery of the "dark matter" inside the cell is revealed
A group of biologists led by Yukiko Yamashita has identified the role of satellite DNA, which does not encode proteins and belongs to the "junk" DNA ("dark matter" of the genome). It turned out that "useless" sections of deoxyribonucleic acid hold chromosomes inside the cell nucleus. The scientists' article was published in the journal eLife (Jagannathan et al., A conserved function for pericentromeric satellite DNA). This is reported by the publication Futurity: ‘Junk DNA’ isn't so useless after all.
Satellite DNA consists of sequences of nucleotides repeating one after another, the sizes of which can vary from one nucleotide pair to several thousand. It is mainly localized in centromeres – specific regions of chromosomes in which sister chromatids are connected to each other (two identical chromatids linked to each other form a characteristic X-shape). Constitutive heterochromatin is formed from it – a region of compact packed DNA that does not contain genes.
Scientists have removed the D1 protein from the cells of the common drosophila Drosophila melanogaster. It is known that this compound binds to centromeric satellite DNA. It turned out that in the absence of D1 in insects, germ cells involved in the formation of sperm and eggs die. Microkernels were formed in them – fragments of the nucleus, which contain only a part of the genome necessary for survival.
"Junk" DNA, or "dark matter" of the genome, is a part of the genome whose role has not yet been established. Previously, it was believed that DNA that does not encode proteins is useless for the body, but now it is known that it can perform structural and regulatory functions.
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