The key difference between uniparental disomy and genomic imprinting is that uniparental disomy refers to multiple sets of processes such as receiving two copies of the chromosome or a part of the chromosome while genomic imprinting refers to the process where one copy of the gene is inactivated.
Uniparental disomy and genomic imprinting are rare occurrences that take place at a molecular level. These processes regulate the gene expression in eukaryotes. Moreover, these processes currently play an important role in disease diagnostics and molecular genetics.
CONTENTS
1. Overview and Key Difference
2. What is Genomic Imprinting
3. What is Uniparental Disomy
4. Similarities Between Uniparental Disomy and Genomic Imprinting
5. Side by Side Comparison – Uniparental Disomy vs Genomic Imprinting in Tabular Form
6. Summary
What is Uniparental Disomy?
Uniparental disomy is the phenomenon where an individual receives two copies of a chromosome. It may also refer to the phenomenon of receiving a part of the chromosome from one parent. Uniparental Disomy is a random occurrence taking place during the development of gametes. The effect of uniparental disomy mainly relies on the inheritance and the expression of the particular genes. Thus, in some instances, uniparental disomy may affect the offspring. Therefore, it can either lead to the overexpression of a particular gene or the loss of function of the gene.
Figure 01: Uniparental Disomy
Uniparental disomy may lead to chromosomal aberrations and certain inheritance disorders. Some of them include Prader-Willi syndrome and Angelman Syndrome. Prader-Willi syndrome is associated with obesity and uncontrolled food intake, while Angelman syndrome leads to disability in intellectual characters and speech impairment. However, uniparental disomy may also lead to the onset of cancers and the expression of tumours. So, this is one of the most potent disadvantages of uniparental disomy.
What is Genomic Imprinting?
Genomic imprinting primarily takes place during the initial stages of development of an organism. Even though each individual inherits two copies of a gene, in most instances, only one gene copy is in its active form, and the other is in the inactive form. Further, it may take place in some genes, where one copy is turned “on”, and the other is turned “off”.
Figure 02: Genome Imprinting
Genomic imprinting is important to maintain the gene constitution in the offspring. Facilitation of genomic imprinting takes place through the methylation process. Methylation of certain bases or histone methylation will lead to the modification of the genome. And, this will lead to genomic imprinting.
Meanwhile, not all genes are capable of undergoing genomic imprinting. However, this also helps in identifying evolutionary relationship patterns. Further, the imprinted genes usually cluster together in chromosome regions.
What are the Similarities Between Uniparental Disomy and Genomic Imprinting?
- Both processes take place in eukaryotes.
- Moreover, both take place at a molecular level.
- Both processes involve genetics and inheritance strategies.
- These processes can be diagnosed with the help of molecular techniques such as Polymerase chain reaction, etc.
- The result may either bring about a drastic effect or remain without any effect depending on the gene position.
What is the Difference Between Uniparental Disomy and Genomic Imprinting?
Uniparental disomy and genomic imprinting are two diverse concepts. Uniparental disomy involves only one parent organism, while genomic imprinting involves both parents. Uniparental disomy takes place at the point of meiosis forming the gametes. In contrast, genomic imprinting takes place in the offspring following fertilization process. So, this is the key difference between uniparental disomy and genomic imprinting.
The below infographic presents more information regarding the difference between uniparental disomy and genomic imprinting.
Summary – Uniparental Disomy vs Genomic Imprinting
In summarizing the difference between uniparental disomy and genomic imprinting; the uniparental disomy is the phenomenon where one parent either donates both copies of one copy of the gene to the offspring. Therefore, this will directly impact on the inheritance patterns of the respective organism. In contrast, genomic imprinting refers to the phenomenon of inactivating one copy of the gene in the offspring. Therefore, genomic imprinting takes place following the fertilization process. However, both these phenomena are important in the regulation of genes in eukaryotes.
Reference:
1. Nicholls, R D. “Genomic Imprinting and Uniparental Disomy in Angelman and Prader-Willi Syndromes: a Review.” American Journal of Medical Genetics, U.S. National Library of Medicine, 1 Apr. 1993, Available here.
Image Courtesy:
1. “Copy neutral LOH” By Jhagenk (talk) – I created this work entirely by myself (CC BY 3.0) via Commons Wikimedia
2. “Imprt” By Arvid Ågren and Andrew G. Clark – (CC BY 2.5) via Commons Wikimedia