Name: shared origins of gene families
Uploaded: 2023-04-30T18:28:42.000Z
Duration: 1 min 57 s
Channel: JoVE

K12 Standards

Pennsylvania State Academic Standards

9-12

Life Science

Inheritance and Variation of Traits

3.1.9-12.P

Gene Families

As cells are frequently dividing, they must also be frequently duplicating their genomes. During this process, mistakes can occur which lead to regions of DNA being duplicated.&#160;
If a duplicated section of DNA contains one or more coding regions, this is referred to as gene duplication. Freed from the constraints placed on the original gene to maintain function, the gene copy can now acquire mutations and may evolve to fulfill a new function within the cell. We refer to genes which have evolved in this manner - through duplication of existing genes in the genome of a single species - as &#8220;paralogs&#8221;.&#160;
Orthologs, on the other hand, is a term used to describe genes in different species that arose from a common ancestor but continued to evolve after one or more speciation events.&#160;
The term &#8220;homolog&#8221; may be applied in both instances, and simply describes genes with a common ancestor. Groups of homologous genes are collectively referred to as &#8220;gene families&#8221;.
Because of their related DNA and resulting protein similarities, genes within one gene family typically produce proteins which perform similar functions.&#160;
For example, hemoglobin and myoglobin are related proteins which both perform o

gene families

Gene families consist of groups of genes proposed to have originated from a common ancestor. Typically these arise through events in which a gene or genes are mistakenly duplicated during cell division. Unlike their parent genes (which are subject to selection pressure to maintain function), these gene copies do not need to preserve their sequences and may evolve at a relatively faster rate.
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes in their own right. When this occurs, we refer to these genes as paralogs - two genes within the same species which evolved from a common ancestral gene.
Another common term when referring to members of a gene family is ortholog. Orthologous genes are those which arose from a common ancestral gene but continued to evolve after one or more speciation events. For example, the gene for the mouse enzyme trehalase would have an ortholog in humans that also makes the trehalase enzyme. However, these genes and their products would be at least partly different in sequence due to the years of evolutionary change since the last mouse and human common ancestor. Therefore, they are orthologs in the same gene family.
The third common term used within gene families is homologous genes. This term is broader and applies to all of the related genes within a gene family.
Additionally, the term superfamily is sometimes used to refer to very large groups of genes and proteins which display enough homology to have shared common ancestry. For these large families, the grouping may rely on mechanistic similarities to determine the scope of the group. As a consequence of their shared genetic inception, the genes within a gene family typically perform related functions. The immunoglobulin superfamily, for example, comprises a large number of genes which code for both soluble and cell surface proteins involved in immunological responses like cell binding or adhesion. The key feature of this family is that the members share a common domain called the immunoglobulin fold - which is critical to their function.

Gene families consist of groups of genes proposed to have originated from a common ancestor. Typically these arise through events in which a gene or genes ...

Education

JoVE Core

Cell Biology

Unit 1

Cells, Genomes, and Evolution

KEY TERMS AND CONCEPTS

shared origins of gene families

Gene families are groups of related genes that share a common origin. They form when genes are copied and then change over time. These related genes can be found within the same genome.

The video also connects gene families to homologous genes and orthologous genes. Homologous genes are genes with a shared evolutionary origin. Orthologous genes are homologous genes found in different species. Gene families help show how these relationships are used to study evolution and related gene functions.

Shared Origins of Gene Families

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Gene families are groups of related genes that share a common origin. They form when genes are copied and then change over time. These related genes can be found within the same genome. The video also connects gene families to homologous genes and orthologous genes. Homologous genes are genes with a shared evolutionary origin. Orthologous genes are homologous genes found in different species. Gene families help show how these relationships are used to study evolution and related gene functions.

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key terms and concepts

Learn how gene families form from shared ancestry and how homologous and orthologous genes help scientists study evolution across species.

Shared Origins of Gene Families | JoVE K12

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Ohio’s Learning Standards and Model Curriculum

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Shared Origins of Gene Families

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