Genetic Chimaeras
Why in news ?
In a recent landmark study, scientists reported successfully generating a live chimaera in non-human primates.
Natural Chimaeras among Humans:
- It can occur when the genetic material in one cell changes and gives rise to a clonal population of cells different from all the other cells.
- Fusion of two fertilised zygotes early in the embryonic stage can also lead to a condition in which two genetic makeups coexist in a single individual.
- Chimerism can also result from twin or multiple pregnancies evolving into a single foetus or a twin foetus being absorbed into a singleton.
- Individuals living with two blood types have been documented. Pregnant women have been known to harbour genetic material of her foetus in the bloodstream during pregnancy.
Chimaeras in Non-human Primates:
Previously, chimaeras have been induced in laboratory settings, of rat-mouse, human-pig, and human-cow in order to ‘generate’ human organs.
While rat-mouse chimerics had a near-normal lifespan, human-pig chimaeras had to be terminated in three to four weeks.
Though such studies have shown promise for growing organs for transplantation, they are limited by the fact that rats, mice, pigs and cows are evolutionarily distant from humans, and will pose biological and technical challenges when being used to grow human organs.
Applications:
- Human-pig chimaeras have been induced in laboratory settings in a bid to develop model systems that could ‘produce’ human organs of a suitable size, anatomy, and physiology.
- Successful application of animal insulin and the more recent use of animal heart valves in human surgeries have saved human lives.
Induced pluripotent stem cells (iPSCs):
- Induced pluripotent stem cells (iPS cells or iPSCs) are a type of pluripotent stem cell that can be generated directly from a somatic cell.
- The iPSC technology was pioneered by Shinya Yamanaka and Kazutoshi Takahashi in Kyoto, Japan, who together showed in 2006 that the introduction of four specific genes, collectively known as Yamanaka factors, could convert somatic cells into pluripotent stem cells.
- Shinya Yamanaka was awarded the 2012 Nobel Prize along with Sir John Gurdon for the discovery that mature cells can be reprogrammed to become pluripotent.
Natural chimaeras among humans
They occur when the genetic material in one cell changes and gives rise to a clonal population of cells different from all the other cells.
The fusion of two fertilised zygotes early in the embryonic stage can also lead to a condition in which two genetic makeups coexist in a single individual.
Source – The Hindu
