Study Links Endogamy To Persistence Of Harmful Genetic Variants In India

Relevance: GS 3- Science and Technology- developments and their applications and effects in everyday life. Achievements of Indians in science & technology; indigenization of technology and developing new technology. Awareness in the fields of biotechnology, Prelims

(Source: The Hindu, 08/7/2023)

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Why in the news?

• The author, Navneet A. Vasistha, Assistant Professor at the Biotech Research and Innovation Center, University of Copenhagen has discussed the genetic trends among the population of South Asia and various subcommunities in India.
• Stark genetic differences were found among people from different regions of the Indian subcontinent and at a community level in India.

What have the studies discovered?

Study 1

• A 2009 study by a team from the Center for Cellular and Molecular Biology found that a small group of Indians were prone to cardiac failures at young ages due to 25 base-pair deletion in their DNA.
  • The 25 base-pair deletion refers to the absence of 25 base pairs in a gene which is crucial in the rhythmic beating of the heart.
  • It was unique to the Indian population and some isolated populations in South Asia.
  • It affects around 4% of the Indian population and is believed to have arisen around 30,000 years ago following the settlement of the subcontinent.

Study 2

• A study by the Institute of Human Genomics at the University of California collected DNA samples from 5000 individuals across India, Pakistan, Bangladesh, and some other South Asian communities like Malays and Tibetans.
• Whole-genome sequencing was performed to discover all instances that either showed changes or lacked or had surplus base pairs.
• Little mixing was found between individuals of different communities which means that endogamous practices have led to conserved genetic profiles.
• Criticism: The genomes studied are not an accurate representation of the subcontinent's diversity.
  • Since the subjects of the study were mostly recruited from hospitals and healthcare providers, it could be biased toward individuals seeking medical intervention.

Why is it concerning?

• Ideally, random mating in a population would lead to greater genetic diversity and lower frequency of variants, which are linked to disorders.
  • However, the practice of endogamy means the genetic profiles were more conserved.
• The Indian population exhibited a higher proportion of homozygous genotypes in comparison to more out-bred populations such as Taiwan.
• Homozygous genotypes are when humans have two copies of the same variant of a gene.
• Genetic variants, which are generally recessive, are more effective in homozygous genotypes.
• South Indian and Pakistani subgroups displayed a high degree of inbreeding while it was much lower among the Bengali subgroup.
• The three subgroups exhibited 300-600 times higher levels of rare homozygous variants.
• The South Asian group displayed a higher number of variants that could disrupt the functioning of genes and some unique variants that were not found in Europeans.
• These variants could impact physiological parameters increasing the risk of cardiovascular disorders, diabetes, cancers, and mental disorders.

Genomic Mapping

• The human genome sequence was last published twenty years ago, at which time several ethnic differences have been identified. However, a detailed map of the Indian genome is missing.
• The University of California study highlighted how India’s genetic diversity could have economic, matrimonial, and geographical implications.
  • It also mentioned the need to change some cultural aspects to improve population health.
• The Department of Biotechnology, GoI, has implemented a mission-mode, multi-institution consortium project called the Genome India Project to identify genetic variations in 10,000 representative individuals across India in the first phase.

Benefits

• Mapping the human genome would help in identifying genes linked to hemophilia, skin color, and cardiac failure.
  • Most medical disorders are genetically complex and occur when multiple genes are simultaneously disrupted.
  • Identifying such unique genetic variants could help develop interventions for major health concerns.
• Determine gene-disease linkages, develop personalized medicine approaches and a better understanding of diseases like cancer.
• It provides data about drug efficacy and its side effects.
• Develop a better understanding of the genetic basis of the susceptibility of crops to various diseases and develop genetic deterrents.

Concerns

• Investment: It requires infrastructure development and investments in improving competency in related fields.
  • This could be implemented through a multi-center collaboration.
• Time: A detailed study of the major characteristics in the genetic profile of the Indian population would require significant amounts of time and resources.
• Accuracy: There are some concerns about the accuracy of genome sequencing measures.
• Use of genetic information: There is very little understanding about the human genome which means that information obtained from such studies is presently unusable.
  • MNCs and foreign organizations which conduct such studies could exploit the many vulnerable communities within the country due to the absence of an adequate regulatory framework.
• Ethics: Whole genome sequencing could have ethical implications with potential downsides such as genetic discrimination, loss of anonymity, and psychological impacts.
• Social issues: The scientific study of genes and their classification could reinforce stereotypes about heredity and racial purity.
  • Genetic puritanism must be abandoned despite cultural and traditional sensitivities as it is the simplest way to prevent major hereditary disorders.

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FAQs

MCQs

Question: With reference to agriculture in India, how can the technique of 'genome sequencing', often seen in the news, be used in the immediate future? (UPSC CSE 2017)

1. Genome sequencing can be used to identify genetic markers for disease resistance and drought tolerance in various crop plants.
2. This technique helps in reducing the time required to develop new varieties of crop plants.
3. It can be used to decipher the host-pathogen relationships in crops

Select the correct answer using the code given below:

(a) 1 only

(b) 2 and 3 only

(c) 1 and 3 only

(d) 1, 2 and 3

Question: At present, scientists can determine the arrangement or relative positions of genes or DNA sequences on a chromosome. How does this knowledge benefit us? (UPSC CSE 2011)

1. It is possible to know the pedigree of livestock.
2. It is possible to understand the causes of all human diseases.
3. It is possible to develop disease-resistant animal breeds.

Which of the statements given above is/are correct?

(a) 1 and 2 only

(b) 2 only

(c) 1 and 3 only

(d) 1, 2 and 3