It is finally time to dive into the world of genetics! Today, I am going to talk about the fascinating results of interbreeding and inbreeding in various species of animals, including ours.

We will begin with the definitions for these two terms:

interbreeding = individuals from different species producing offspring

inbreeding = individuals from the same gene pool producing offspring

Are these two reproductive situations natural? The answer is YES! Sometimes…

They both occur in nature. Interbreeding is actually the reason why Neanderthal genes have not completely disappeared after the species’ extinction, as shown in the photo below:


Some examples of modern interbreeding are grolar bears and mules:



As long as two organisms are similar enough (genetically speaking) interbreeding can occur. Ligers, tigons, wholphins, leopons, zorses, hinnies … the list goes on and on! It is not yet clear if humanzees are a real thing or not, since conclusive experiments are hard to accomplish in an ethical fashion.

The offspring of two different species usually obtains traits from both parents, but likely becomes infertile due to the different number of chromosomial pairs. Interbreeding is also known as cross breeding or hybridization.

Inbreeding, on the other hand, occurs when a population is isolated for too long. It can lead to devastating mutations in the next generations. Two good examples are the amish communities and the royal families:



Domestication is a common situation when artificial inbreeding occurs. Wild animals are selectively bred in captivity in order to enhance beneficial traits or remove detrimental ones. Here’s what happened to wolves:


Pugs, bulldogs and chihuahuas might be cute, but they all have mutations and health issues related to them. French bulldogs are a good example of a dog breed where artificial insemination is required in order to obtain litters (80% of the time).

Human inbreeding (incest) has been banned in most cultures. Sadly, animal inbreeding continues to be completely acceptable when it comes to captive bred white lions, white tigers or other popular zoo residents/pets.

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