Page 10 - Success Plus English Language and Literature Class 10

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3. genetically engineered pigs for human organ transplant

1. Organ transplantation is a medical 4. In recent times, both of these problems
procedure in which an organ, such as a have been dealt with by the discovery of
heart, kidney or liver, is removed from one a breakthrough gene-editing tool called
body and placed into another to replace CRISPR*. Using this tool, scientists have
a damaged or missing organ. Due to been able to identify and suppress those
various medical, legal and ethical factors, genes in pigs that trigger rejection of
the number of people who require organs organs by the human immune system.
are far more than the number of people Scientists have also used CRISPR to create
who can donate them. Therefore, scientists genetically modified piglets that are free of
have been trying to find alternative twenty-five viruses that are considered to
sources of readily available organs for be harmful to humans.
transplantation.
5. The other scientific breakthrough in the
2. Over the last century, attempts have been field of xenotransplantation is the creation
made to transplant organs from various of human-pig hybrids or ‘chimeras’.
animals such as rabbits, sheep and pigs to The process involves injecting of human
humans. When organs are transplanted stem cells into pig embryos and growing
from one species to another, such as from human organs inside the pigs, which can
pigs to humans, the procedure is known as be harvested and used for transplantation.
‘xenotransplantation’. Pigs have often been The organs grown by this method can also
considered as the best option to obtain be genetically engineered to be compatible
organs from. They are readily available with the recipient, thereby eliminating fears
in large numbers. The size of their organs of rejection.
matches that of human organs and they 6. It is important to mention here that the
both have similar functions.
techniques outlined above are still very
3. However, there are problems as well. much in the trial stage, and it may be years
Despite the compatibility, the human before they can be successfully and safely
body’s immune system often rejects implemented in actual surgery. Moreover,
the donated organs and destroys them. there are religious, spiritual and ethical
Another big problem is the presence of concerns regarding the use of pigs for
several viruses in the pig’s body, which are human transplantation, which need to be
harmless to them but are thought to be addressed as well.
very harmful to humans.

A Answer the following questions based on the passage you have just read.
(4 × 2 = 8 marks)

1. Why are scientists looking for alternative sources of organs for transplantation?
2. Why are pigs considered the best option to obtain organs from?

3. What are the major problems associated with organ transplantation from pigs?
4. How has CRISPR helped in solving the problems associated with organ transplantation from
pigs?

*Clustered Regularly Interspaced Short Palindromic Repeats

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