RRI.CO.ID,Jakarta - Amazon mollies are small fish that live in fresh water in Mexico and Texas. All Amazon mollies are female.

They do not need a male to have babies. The babies are exact copies, or clones, of the mother.

This is strange for scientists. Most animals need males and females to make babies. Mixing genes from two parents helps keep a species strong and prevents extinction. So people wondered how these all-female fish could survive for so long without sex.

A new study in the journal Nature gives an answer. It shows that Amazon mollies do not suffer from the problems we expect in animals without sex.

They have a special way to stay healthy. This helps us understand how other animals that clone themselves also survive.

Named after the female warrior race from Greek mythology, Amazon mollies are about as big as a thumb. They first appeared 100,000 years ago.

A female Atlantic molly mated with a male Sailfin molly. Their babies could make clones of themselves.

Today, Amazon mollies still need to mate with males of other fish species to start pregnancy. But the babies only get DNA from the mother, not the male.

Scientists found Amazon mollies in 1932. They were the first animals with a backbone known to clone themselves. Other animals like Komodo dragons can do it too, but only sometimes.

Amazon mollies only clone themselves. Computers predicted they should die out after 10,000 years because bad changes in DNA would build up.

But the study showed Amazon mollies fix their DNA. They use a process called “gene conversion.” This process copies good DNA to replace bad DNA. It works like the gene mixing that happens in sexual reproduction. Because of this, natural selection can still remove bad changes. So the fish stay healthy.

This discovery is important. Scientists think other animals that clone themselves may use the same trick. More research is needed on plants, animals, and tiny microbes. Understanding this could also help humans. For example, cancer cells are clones with bad DNA. Learning from these fish may help us find new ways to treat cancer.

Source: National Geographic