How chromosomes find their partners
For a long time, so-called satellite DNA was considered largely worthless. Now, ETH Zurich researchers have shown in fruit flies that these repetitive sections of genetic material act as a kind of barcode, enabling the correct chromosomes to recognize one another.
For centuries, satellite DNA was dismissed as useless "junk DNA" in the genetic material of fruit flies and other animals. However, ETH Zurich researchers have discovered that these repetitive sections play a crucial role in chromosome pairing during meiosis. Meiosis is the process where a cell's double set of chromosomes is halved to form a single set, resulting in sperm or egg cells.
During this process, chromosomes from both the mother and father must find each other and temporarily pair up in the cell nucleus. If this doesn't happen correctly, resulting chromosomes could be distributed improperly during fertilization, leading to genetic errors that could cause infertility or other issues. The researchers found that unique patterns in satellite DNA act like barcodes, helping the chromosomes recognize and pair with their correct partners.
Removing the barcode from two different chromosomes led to incorrect chromosome pairing. While D1 protein plays a role in binding matching chromosomes, any alteration in the barcode pattern can cause partner selection to go wrong. This mechanism of satellite DNA functioning as a recognition aid could also explain how new species arise through geographical isolation, leading to chromosome barcode divergence that prevents reproduction between populations.
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