Somatic Genetic Variants

August 28, 2023

GS Paper III Science and Technology

Context:

Recently, there has been an explosion in the amount of data on somatic variants due to increasing ability to sequence the genetic material in individual cells using advanced microfluidics and high-throughput sequencers.

About Human Genome

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The human genome is the blueprint of our genetic makeup and it has 23 pairs of chromosomes, one inherited from each of our parents.
Process of Human Genome Formation:
- The ovum and the sperm carry these blueprints from our parents.
- After fertilisation, the combined single cell starts to divide by copying the genetic material to nearly a trillion cells that make up the human body.
Various studies have estimated that there is an error rate of 0.64-0.78 mutations per billion base pairs per division.

SMaHT Network

The U.S. recently launched a programme focused on understanding the breadth of somatic mosaicism called the Somatic Mosaicism across Human Tissues (SMaHT) Network.
Mosaicism is when a person has two or more genetically different sets of cells in their body.
Aim: Discovering somatic variants, developing tools and resources with which to study them, and improving the ability to analyse, interpret, and organise them in different biological and clinical contexts.

About Somatic Genetic Variants

An error that occurs in the DNA after birth but during development is called a somatic genetic mutation.
- For example, Skin Cancer, Lung Cancer etc.
Their occurrence is driven by the repeated copy and pasting of the genome which means there will be more somatic genetic mutations in the older individuals.
Sometimes, a somatic genetic mutation can render a cell fitter than others, which lead to the formation of tumours. So these mutations are called driver mutations. It plays an important role in the development of cancers.