What is Parthenogenesis?


Parthenogenesis is a form of asexual reproduction in which growth and development of embryos occur without fertilization. That means that the embryos or eggs grow into adult organisms without ever being fertilized.

That is not usually the case. Parthenogenesis usually occurs in the absence of males. If there are no males around to fertilize the eggs, then this phenomenon can occur. It can also occur during favorable environmental conditions.

Parthenogenesis is more efficient than sexual reproduction, because in a lot of cases the offspring are receiving just a full copy of the mother’s genetic material and there’s no room for error there.

It’s the exact copy of what the viable adult mother was having for genetic material. However, this does lower genetic diversity. When there aren’t two parents contributing and forming a mixture of genetic material for the offspring, the diversity is not going to be very great within that population.

Parthenogenesis occurs naturally in plants and in some invertebrates. Those are your animals without backbones, such as your nematodes, water fleas, aphids, some bees, some parasitic wasps, and there may be a few more.

Then, it can occur in a few vertebrates. It isn’t as common in vertebrates, but it is possible. Some examples of vertebrates that could have parthenogenesis occur are some fish, amphibians, reptiles, and very rarely birds.

Parthenogenesis can produce full clones, which means that the offspring are going to have all of their mother’s genetic material, usually formed without meiosis.

During meiosis, the cells are going to divide and will often result in a haploid zygote. Then, the offspring is only going to have half of that genetic material, sometimes somewhere between half and the full amount.

A full clone is going to have all of the mother’s genetic material. It will an exact copy of the mother. Parthenogenesis can also result in half clones.

These are going to be offspring containing only a portion, at least half but possibly more of their mother’s genetic material. These offspring are formed with meiosis.

They’re going to get at least half of their mother’s genetic material. Some of those alleles are going to become diploid and some are not. It’s at least half of the genetic material, possibly more, where full clones are going to have all of their mother’s genetic material.

Parthenogenesis is a special form of asexual reproduction where embryos are able to grow to adulthood without ever being fertilized.



by Mometrix Test Preparation | Last Updated: August 15, 2019