The key difference between hypermorph and neomorph is that hypermorph alleles produce the same active product with an increased activity while neomorph alleles produce an active product with a new different function.
A mutation is a change in the nucleotide sequence of a gene. As a result, the gene cannot produce the same product as the wild type allele. There are several types of mutant alleles including amorph hypomorph, hypermorph, neomorph and antimorph. Hypermorph alleles produce more of the same active product. This can occur via increased transcription or by changing the product to make it more efficient or effective at its function. Neomorph alleles produce an active product with a novel function that the wild type allele doesn’t have. Both of the mutations are gain of function mutations, which cause the gene to increase the gene function or to gain an atypically new function.
CONTENTS
1. Overview and Key Difference
2. What is Hypermorph
3. What is Neomorph
4. Similarities Between Hypermorph and Neomorph
5. Side by Side Comparison – Hypermorph vs Neomorph in Tabular Form
6. Summary
What is Hypermorph?
Hypermorph is a mutant allele that produces the same active gene product. But, compared to the wild type, it has a greater effect or increased activity. It is a type of gain of function mutation. It increases the final product via increased transcription or by changing the product to make it more efficient in its function. Therefore, the expression of mRNA or protein increases with respect to the wild type gene. Moreover, a hypermorphic mutation can result in an altered gene product which has an increased level of activity. As an example of hypermorphic mutation, dominant alleles in Caenorhabditis elegans gene lin-12 result in more cells transforming to another cell type due to increased gene dose.
What is Neomorph?
Neomorph is a type of mutation in which the allele produces an active product with a new function. Therefore, the function differs from the wild type allele function. Neomorphic gene mutation causes a new gene function or activity. It can also cause a new pattern of gene expression. Like hypermorphic mutation, the neomorphic mutation is also a gain of function mutation which produces an altered gene product.
Figure 01: Antennapedia Mutation
In neomorphic mutation, the dose of wild-type has no effect on the phenotype. An example of neomorphic mutation is the AntpNs mutation resulting in the expression of Antennapedia (Antp) gene from a transposable element in antennae of Drosophila. Nobel Prize-winning geneticist, H.J. Muller first described the neomorph in Drosophila in 1932.
What are the Similarities Between Hypermorph and Neomorph?
- Hypermorph and neomorph are two mutant genes.
- Both hypermorph and neomorph are associated with the gain of gene function.
- In both types, alleles are almost always dominant to the wild type allele.
- Mutant phenotypes shown by both mutations are more severe in the homozygous genotype.
- Hermann J. Muller described the terms hypermorph, neomorph and three other mutation types.
What is the Difference Between Hypermorph and Neomorph?
Hypermorph is a gain of function mutation which causes an increase in normal gene function while neomorph is a gain of function mutation which causes novel gene function. So, this is the key difference between hypermorph and neomorph. Moreover, hypermorphic mutations cause increases in normal gene function whereas neomorphic mutation leads to a new function.
Summary – Hypermorph vs Neomorph
Hypermorph and neomorph are two gain of function mutations. Hypermorph mutation causes increased or normal gene function while neomorph mutation causes novel gene mutation. Generally, hypermorph mutation shows the excessive gene expression in order to produce increased gene activity. Both hypermorph and neomorph mutations produce altered gene products. Moreover, both mutations are dominant. This is the summary of the difference between hypermorph and neomorph.
Reference:
1. Takiar, V, et al. “Neomorphic Mutations Create Therapeutic Challenges in Cancer.” Oncogene, U.S. National Library of Medicine, 23 Mar. 2017, Available here.
2. “Muller’s Morphs”. En.Wikipedia.Org, 2020, Available here.
Image Courtesy:
1. “Antennapedia2” By toony – Own work (CC BY-SA 3.0) via Commons Wikimedia