According to the laws of nature, reproduction of living things usually requires both male and female. But a certain fish that lives in the waters of Mexico and South Texas continues to completely defy this general rule. This fish called Amazon Molly has no male. The name derives from a dominant female-only warrior force in Greek mythology. Amazingly, they have survived without men for the past 100,000 years.
This species uses a remarkable process called gynogenesis for reproduction. Females need sperm from males of other species to produce offspring. But that sperm starts the process of egg growth. The genes of male fish are not passed on to the young and are destroyed immediately. Each resulting puppy is genetically identical to its mother.
Most life on Earth depends on sexual reproduction. This leads to the exchange of genes and creates a healthy generation that can fight disease. According to scientific theory, without such a reproductive system, an organism would accumulate bad genes and eventually the species would disappear from the earth. But as Amazon Molly has shown, this assumption may not always be true. Another tiny animal called a rotifer has also been collecting genes from non-males for billions of years.
German scientist Eduard Reismeyer and his colleagues recently uncovered the mystery of the Amazon’s dirt. They discovered that the species evolved from the mating of two different molly fish around 100,000 years ago, giving them separate gene pools. Whenever something goes wrong with a gene in their body, they repair the damaged part by copying the exact part from another healthy gene in their body. This system can be compared to the copy and paste process of a computer.
They often make this repair in areas where the risk of gene damage is greatest. This important discovery is great news not only for zoology but also for human medicine. Terrible diseases like cancer are caused by genetic aberrations. Amazon Molly shows us that we don’t have to rely solely on sexual reproduction to keep genes healthy, but that nature has other beautiful alternative systems.