Name: sox10 and multiple traits in pleiotropy
Uploaded: 2019-03-11T09:21:17.000Z
Duration: 1 min 33 s
Channel: JoVE

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Heredity- Inheritance and Variation of Traits

LS.Bio.7.3

Pleiotropy

During pleiotropy one gene influences several unique phenotypes.

For example, in humans, an abnormal copy of the SOX10 gene, with a region deleted, may cause individuals to have a white forelock, different colored irises, and regions of unpigmented skin. Thus this gene can affect hair, eye, and skin phenotypes. And these atypical traits are symptoms of a larger disorder called Waardenburg Syndrome Type 4, abbreviated WS4.

However, SOX10&#39;s role isn&#39;t limited to pigmentation, as the large intestines of WS4 patients lack components of the nervous system that control intestinal contractions. As a result, waste blockages and enlarged colons are characteristic of WS4. So SOX10 also shapes bowel phenotype.

Importantly, it&#39;s expression during early development may explain this gene&#39;s effects, as its product is found in forming pigment cells and certain nerve tissue. Interestingly the SOX10 protein is also observed in components of the future ear, suggesting that this gene contributes to other phenotypes, a hypothesis supported by the hearing impairments and deafness occasionally accompanying WS4.

So, sometimes multiple traits associated with a disorder result from an individual pleiotropic gene.

pleiotropy

Pleiotropy is the phenomenon in which a single gene impacts multiple, seemingly unrelated phenotypic traits. For example, defects in the SOX10 gene cause Waardenburg Syndrome Type 4, or WS4, which can cause defects in pigmentation, hearing impairments, and an absence of intestinal contractions necessary for elimination. This diversity of phenotypes results from the expression pattern of SOX10 in early embryonic and fetal development. SOX10 is found in neural crest cells that form melanocytes, which are involved in pigmentation and also in the early development of the ear. SOX10 is also expressed in nerve tissue that eventually contributes to the enteric nervous system in the gut, which controls the contractions necessary for waste elimination. In this way, SOX10 exhibits pleiotropic effects, because it influences multiple phenotypes.

<h4>Pleiotropic Effects of SOX10</h4>

Pleiotropy can arise through several mechanisms. Gene pleiotropy occurs when a gene has various functions due to encoding a product that interacts with multiple proteins or catalyzes multiple reactions. For example, in humans, an abnormal copy of the SOX10 gene, in which a region is deleted, can lead to developmental defects that include a white forelock, different-colored irises (e.g., one blue and one brown), and regions of unpigmented skin. These traits are all symptoms of a disorder called Waardenburg Syndrome Type 4, or WS4, an autosomal recessive disorder that results in multiple pigment defects. The pleiotropic effects of SOX10 in WS4 extend toward additional symptoms seemingly unrelated to pigmentation, such as hearing loss. Individuals with WS4 also suffer from a lack of intestinal contractions, resulting in an enlarged colon and difficulties eliminating waste. These symptoms indicate that, in addition to affecting pigmentation, SOX10 also impacts hearing and contributes to an abnormal bowel phenotype.

<h4>Early Development Expression Patterns</h4>

The ability of SOX10 to exert its pleiotropic effects may be explained by its expression in early embryonic and fetal development, during which it is found in neural crest cells that eventually lead to the formation of pigment cells called melanocytes. In addition to pigmentation, melanocytes influence hearing, as they are found in the developing ear. SOX10 is also expressed in ganglion cells of the terminal hindgut that contribute to the formation of the gastrointestinal tract and control intestinal contractions. This explains the elimination problems and enlarged colons in some WS4 individuals. Therefore, SOX10 is an example of a pleiotropic gene, because it has an impact on several developmental processes and influences multiple phenotypic traits.

Pleiotropy is the phenomenon in which a single gene impacts multiple, seemingly unrelated phenotypic traits. For example, defects in the SOX10 gene cause ...

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KEY TERMS AND CONCEPTS

sox10 and multiple traits in pleiotropy

Pleiotropy is when one gene affects more than one trait. The SOX10 gene is a clear example because it can influence pigmentation, hearing, and intestinal movement. These traits may seem unrelated, but they can all be linked to the same gene change.

In humans, a deleted region in SOX10 can cause Waardenburg Syndrome Type 4, or WS4. WS4 is an autosomal recessive disorder, which means a person usually inherits two altered copies of the gene. Common signs include a white forelock, different-colored irises, and patches of unpigmented skin. The syndrome can also cause hearing loss.

SOX10 affects more than pigment because of where it is active during early development. It is found in neural crest cells, which give rise to melanocytes, the cells involved in pigmentation. These cells also help with early ear development, which helps explain the hearing problems seen in WS4.

SOX10 is also expressed in nerve tissue that later contributes to the enteric nervous system in the gut. This system controls intestinal contractions needed for waste elimination. When SOX10 does not work properly, some individuals develop an enlarged colon and have trouble eliminating waste. These effects show how one gene can shape several developmental processes at once.

SOX10 and Multiple Traits in Pleiotropy

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Pleiotropy is when one gene affects more than one trait. The SOX10 gene is a clear example because it can influence pigmentation, hearing, and intestinal movement. These traits may seem unrelated, but they can all be linked to the same gene change. In humans, a deleted region in SOX10 can cause Waardenburg Syndrome Type 4, or WS4. WS4 is an autosomal recessive disorder, which means a person usually inherits two altered copies of the gene. Common signs include a white forelock,...

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key terms and concepts

Explore how the SOX10 gene affects pigmentation, hearing, and gut movement in Waardenburg Syndrome Type 4, a classic example of pleiotropy.

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Heredity: Inheritance and Variation of Traits

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SOX10 and Multiple Traits in Pleiotropy

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