What is the Difference Between Orthologous and Paralogous Genes?

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Orthologous and paralogous genes are both types of homologous genes, but they have distinct differences:

  • Orthologous genes are found in different organisms and are derived from a single common ancestral gene present in the common ancestor of those organisms. They diverge after a speciation event, but the gene and its main function are conserved. Generally, orthologous genes maintain a similar function.
  • Paralogous genes are genes present in a particular organism that are related to each other through a gene duplication event. They are found within a single species due to duplication and can have different functions. Some paralogous genes can have physiologically significant effects, while others may have evolved to perform different functions than the ancestral gene.

In summary, orthologous genes are homologous genes found in different species due to speciation, and they usually maintain a similar function. In contrast, paralogous genes are homologous genes found within a single species due to gene duplication, and they can have different functions.

Comparative Table: Orthologous vs Paralogous Genes

Here is a table comparing the differences between orthologous and paralogous genes:

Feature Orthologous Genes Paralogous Genes
Definition Homologous genes found in different species due to separation by speciation. Homologous genes found within a single species due to duplication.
Function Generally perform the same function as the ancestral gene. Can have different functions other than the function of the ancestral gene.
Origin Diverged after a speciation event. Diverged within a single species due to gene duplication.
Location Found in different species. Found within a single species.
Duplication Result of a speciation event. Result of a gene duplication event.

In summary, orthologous genes are homologous genes found in different species, while paralogous genes are homologous genes found within a single species due to duplication. Orthologous genes generally perform the same function as the ancestral gene, whereas paralogous genes can have different functions.