Population Genetics Among Animals – What Is It?

Population genetics among animals makes it possible for us to estimate a species’ conservation status in its natural environment.
Population genetics among animals - What is it?

Population genetics among animals is a branch of biology. This branch treats DNA, genetics, genetic drift, demographic Stochastics, etc. The exciting world of genes can be confusing because it is full of terms that can make it spin around in your head, even on the most knowledgeable person. For that reason, we want to take the opportunity and tell a little about the relationship of genetics to animal populations in an accessible way to make it more understandable.

In our opinion, this topic is very exciting, and the basis of our article will be the information from population studies with amphibians. One of our editors has had the opportunity to be part of a team at the  Museo Nacional de Ciencias Naturales (Natural Science Museum) in Madrid for two years. So today we tell you about the knowledge he has acquired during this wonderful time.

Fundamental principals

Genetics is the branch of biology that seeks to understand and explain the transfer of biological inheritance from one generation to the next. Genes are devices that store information. DNA segments thus contain instructions on how the body’s cells should function. To simplify, we can all say that we all have two copies of each gene that contains information. One of these we have inherited from our father and the other from our mother.

  • The genotype of each individual is part of specific genetic information in the form of DNA. The genome of each animal species represents different variations in many of its genes, which makes them different from the rest of all species.
  • Similarly, the expression of genes in a given environment is called a phenotype. They are about physical and behavioral characteristics. For example, a gene may encode eye color, and brown eyes are then the resulting phenotype.
Illustration of a DNA chain.

How can these conditions be applied to population genetics among animals?

The key to population genetics among animals is about understanding the inheritance patterns from parents to offspring. Let’s take the above example of amphibians:

  • Imagine a pond with 300 frogs of the same species that make up a population. 100 of them are females and 200 are males. One can make this type of estimate using Petersen’s formula.
  • In the spring, when the rain comes, you can see that there are many strings of floating eggs in the pond. Each string is full of young people who of course have a father and a mother.
  • So how many of the males and females in the population participated in this reproductive episode? Which female laid the most eggs? Is there a male that mated with more than one female?
  • Genetic studies try to answer questions like these.

Decipher the offspring

Relationships can be estimated using samples from adults in an animal population, as well as a representative group of offspring. After all, offspring inherit their genes from both their parents, right? One can determine who is the parent through a DNA test, the result of the combination of DNA from two adults in a given population.

This can to some extent solve previously asked questions and also provides insight into an important parameter:

  • The number of animals living within a population is not equal to the number of times they reproduce within it.
  • The effective population number refers to adults who have been confirmed to have reproduced. This is done with the previously described techniques.
  • Here is an example with the previous population of frogs that we mentioned. So there are 300 frogs in the pond. Nevertheless, genetic studies confirm that only 60 of them reproduced that year. It’s a completely different scenario, right?
A frog jumps in a swamp.

Population genetics among animals and its focus on conservation

These types of genetic studies are essential when it comes to species conservation.

For example, if only 60 of our frogs reproduce in a population of 300 individuals, then that is a cause for concern. This is because a reduced number of reproducing individuals results in a decrease in the genetic variation within a population. This lack of variation can lead to greater vulnerability to environmental changes, which in the most extreme cases can lead to the species becoming extinct.

Therefore, it is important to carry out this type of basic zoological studies. Mainly because they provide information on how wild animal populations work, at least on a genetic level.


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