Parthenogenesis in amphibians

Parthenogenesis is a special way some animals can have babies without a partner. In this process, eggs grow into new animals all by themselves, without needing to be fertilized by a sperm cell. This means the new baby comes from just one parent.

In the world of amphibians, which includes frogs, salamanders, and caecilians, parthenogenesis has been seen in many frog and salamander species. Scientists have found that these animals can make clones of themselves this way. However, this process has not been observed in caecilians yet.

Parthenogenesis is related to another way animals reproduce called hybridogenesis. In hybridogenesis, fertilization happens, but the DNA from the father is not passed to the next generation. This shows how nature has many ways to help animals reproduce and survive.

Artificial parthenogenesis

Scientists have found ways to help frogs grow without needing to be fertilized by a male. In 1911, a scientist named Oscar Hertwig used special sperm that had been weakened to help frog eggs start growing. This made almost normal baby frogs. Later tests showed that mixing eggs from one type of frog with weakened sperm from another could also work.

Other ways, like using a needle to gently prick the eggs, have also helped frogs grow on their own. These tests have led to fully grown frogs, including some that look different from normal frogs.

Parthenogenesis in nature

Salamanders are animals that can make babies without a father. This way of having babies is called parthenogenesis. Scientists think this way of having babies started a long time ago.

Many frogs and salamanders that use this way of having babies come from mixing between two very similar groups. For example, the edible frog is a mix of two other frog groups. Some salamanders also come from mixing between different salamander groups. Even though their moms come from one group, these salamanders do not have DNA from a specific old salamander group called Ambystoma barbouri.

Some of these special salamanders have extra chromosomes. Chromosomes are like tiny packages of DNA. Having extra chromosomes is common in these animals and can happen when different groups mix. For instance, some salamanders have three sets of chromosomes, while others have four. This mixing affects how their bodies grow and can make it harder for their eggs to hatch.

Modes of parthenogenesis and parthenogenetic-like reproduction in amphibians

Parthenogenesis is a special way some animals can have babies without needing a partner. In amphibians like some frogs and salamanders, this means eggs can grow and develop all by themselves. One way this happens is called gynogenesis, where an egg starts to divide after touching a sperm cell, but the sperm’s genes aren’t used. This has been seen in some salamander species.

Another way is hybridogenesis, where females mate with males from related species. The females use the male’s genes to help make eggs, but the male’s genes aren’t passed to the next generation. This is common in some European water frogs. There is also a process called kleptogenesis, where genetic material from both parents mixes, helping to keep genetic diversity in some salamander species.