An astonishing amount of DNA is found in the cells of a species of starfish that is widespread throughout the world. The creature has a small, disc-shaped body and long arms (Amphiphilus squamataThe genome is several times larger than that of other snakes.
This is because this species undergoes a process called polyploidy, during which its chromosome sets are duplicated multiple times. Royal Society for Open Science “They have amazing genetic diversity,” said Tim O’Hara, co-author of the new study. “Instead of evolving into separate species over time, bloodlines mix easily, creating genetic diversity. But sometimes they merge their genomes, so that they end up with four or more copies of each gene, it turns out.” Newsweek From his report.
Amphiphilus squamata. Image: Javier / Wikimedia
Strange starfish replicates its DNA
According to the press release, the species’ genome is so diverse that it “cannot be described as a single species.” But how did they manage to do it? Polyploidy is a natural genetic process that results in an organism having more than two sets of chromosomes. Most animals, including humans, have one set of chromosomes from each parent. Polyploidy means they have three, four, or even more sets.
This can result in changes in size, growth, and other characteristics of a particular species and can also occur naturally. It is most common with plants and can sometimes make them larger or more resistant. The best examples of this from the plant kingdom are wheat, potatoes, and strawberries, which are also polyploid.
There are two types of polyploidy. Autopolyploidy occurs when an organism has multiple sets of chromosomes derived from a single species. Allopolyploidy occurs when an organism has sets of chromosomes from different species, often resulting from hybridization between two species followed by chromosome duplication.
According to the authors, this is a very rare phenomenon in animals and is often associated with asexual behavioral complexes, which often have much larger population sizes and more extensive geographic areas than their diploid sexual relatives.
This can result from hybrids between two species, which do not end in sterility as usual, but have twice the number of chromosomes. These hybrids can then cross again with the original species and thus produce offspring with an increased number of chromosomes, which has already been observed in milkweeds and marsupials.
According to the researchers, although rare in the animal kingdom, these snake-armed species may have become polyploid by mixing with different species.
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