Whose animal has the most genetic diversity? A butterfly with 20 different colours? A bacterium that divides every 20 minutes and accumulates genetic mutations?
It turns out that the new record holder is a fungus that grows on decayed wood. On the other hand, the genetic diversity of the lynx is minimal. That’s terrible news for the lynx because genetic variation is beneficial to species. After all, it helps them to respond to changes in their climate.
So, what is genetic variation, and how can animals acquire a large amount of it?
According to Asher Cutter, a professor in the Department of Ecology and Evolutionary Biology at the University of Toronto, genetic diversity is a test of how often two pieces of DNA from the same genomic position differ from one another within a population. DNA is made up of nucleotides made up of bases (represented by the letters A, T, C, and G) and their backbones. Nucleotide diversity, or the number of locations within the genome where two people of the same species are supposed to have different DNA bases, is a measure of genetic diversity.
According to a 2015 report published in the journal Molecular Biology and Evolution, the split gill mushroom (Schizophyllum commune) has a nucleotide diversity of up to 20%. According to the research, this is the highest level of genetic variation ever seen eukaryote or an organism with a nucleus. In other words, approximately 20 out of every 100 locations in the genomes of two different mushrooms would have different DNA bases. According to a 2013 review published in the journal Proceedings of the National Academy of Sciences by Cutter and colleagues, this is more genetic diversity than the previous record holder. The roundworm Caenorhabditis Brenner had a nucleotide diversity of 14.1 percentage. These species are genetically hyperdiverse, described as having a nucleotide diversity of more than 5%. The nucleotide diversity in most plants and animals is less than that. Humans, by contrast, have a nucleotide diversity of around 0.1 percentage, according to Cutter. Bacteria and viruses, according to Cutter, have a lot of genetic variation. However, since organisms are described differently in those groups, it’s challenging to make an apples-to-apples comparison of genetic variation between bacteria and viruses. On the one hand, and eukaryotes on the other, according to Cutter. For the sake of convenience, we’ll focus on the genetic variation of eukaryotes, which includes all mammals, plants, and fungi on the planet.
According to Cutter, the mutation rate, population size, and population stability are all critical factors in a species’ genetic diversity. According to him, genetic diversity is created by evolution, so the higher the mutation rate and the more mutations a species acquires, the greater its genetic diversity. Similarly, Cutter pointed out that the larger the population, the more copies of a genome are available to accumulate the mutations that lead to genetic diversity. Conversely, the bigger the people, the lower the likelihood of genetic diversity. The number of people in a reproducing group and thereby passing on genetic material is the subject of gene diversity researchers. The adequate population size is the term for this figure. According to Cutter, despite being equal to the entire population, the proper population size can be much lower. The genetic makeup of the resultant population would be poorer if a population experiences a bottleneck, or an accident that drives out a large portion of the people, spends some time in a smaller community, and then recovers, he said. According to Live Science, this happened to the western European bison (Bison bonasus), which was almost extinct after World War I, with only 12 individuals remaining in the wild.
What’s the difference between bison and buffalo?
a lot of variety
The split gill mushroom, which has a high level of genetic variation, can be found on every continent except Antarctica, giving it a population size of millions. According to the 2015 paper, the mushroom has an extraordinarily high mutation rate — almost ten times that of the fruit fly Drosophila melanogaster. According to the authors of the study, both of these factors are likely to contribute to the mushroom’s high genetic diversity.
Cutter added that the nematode C. Brenner’s hyper diversity is possibly explained by its massive adequate population number, which is also in the millions. “The species is found in tropical areas of the world, where [the worms] consume bacteria in rotting fruit and rotting foliage, which is an extremely rich food supply available for most of the year,” Cutter said. They’re also thin, being around 0.04 inches (1 millimetre) in length, allowing a large number of worms to survive in a small room. “We believe that [those factors] enable them to reach truly immense population numbers, and that this is what contributes to their genetic diversity,” Cutter said.
According to Cutter, genetic variation is significant because it enables animals to respond to changes in their climate. “There is no raw material for nature to work on if a population has very little genetic diversity,” he said. If a disease emerges, that destroys animals by attacking a specific variant of a gene. That version is the only one the species has. The condition can wipe out the entire species. On the other hand, if the species has genetic variation within the gene, one version of it can cause an organism to resist the disease and thus save the species.
a lack of diversity
The lynx is one breed that faces those dangers. According to José Godoy, a molecular ecologist and conservation geneticist who studies lynx population genomics at the Spanish National Research Council’s Doana Biological Station, the Iberian lynx (Lynx pardinus) has a nucleotide diversity of just 0.026 percentage, one of the lowest of any animal. According to Godoy, the Iberian lynx has very little genetic diversity because it has seen some population bottlenecks over the years, keeping its adequate population size below 300. Godoy told Live Science that the country’s productive population had dropped to 30 by the end of the twentieth century. Since the entire population is lower as a population shrinks, mutations that move into the bottleneck, including damaging mutations, can have a more significant population-wide effect. Ten harmful mutations in a population of 1,000 people, for example, would have a negligible impact than ten harmful mutations in a population of 100 people. As a result, “low genetic diversity caused by recent bottlenecks is followed by the accumulation of mildly deleterious variance, which will limit overall fitness,” Godoy said. He believes that the Iberian lynx’s poor genetic diversity is to blame for its low reproductive success and high prevalence of diseases that are most definitely genetic. According to the International Union for Conservation of Nature (IUCN) Red List, the endangered species faces threats such as poaching, habitat destruction (due to both climate change and human development), and disease-related loss of its host (rabbits). According to Godoy, the Eurasian lynx has poor genetic diversity.
Aside from the dangers it faces, the lynx has a poor density because it is at the top of the food chain. Big apex predators would have fewer numbers than the smaller species they consume to have enough food. “Carnivores, particularly solitary-type carnivores like the lynx, have very low genetic diversity due to their low abundance,” Cutter said. “You see something similar in the cheetah,” he said. The genetic diversity of the big cat is just 0.02 percentage. Although human genetic diversity is much higher than that of the lynx (about 0.1 percentage), it is “pretty low when you consider the fact that there are many billions of humans on this planet,” according to Cutter. “And the explanation for that is that we’ve just had billions of people for a very short time,” he said. “Mutations take time to accumulate in a population as it evolves, resulting in genetic diversity.”
The human successful population scale has been projected to be on the order of 100,000 in recent times. According to Cutter, the long-term prediction is an order of magnitude smaller, at about 10,000. Although we don’t have millions of people like the split gill fungus, we have a much larger population than the Iberian lynx. Cutter believes that if humans maintain their vast population for thousands of years, our genetic diversity will increase as well.