Assertion (A): The mtDNA haplogroups M31 and M32 observed in the Onge and Great Andamanese populations represent ancient maternal lineages that have undergone in situ evolution on the Andaman Islands, isolated since the initial Out-of-Africa coastal migration approximately 50-70 thousand years ago.
Reason (R): Complete mtDNA sequencing revealed that the coding region mutations defining M31 and M32 do not overlap with those of known Indian, East Asian, or Oceanian haplogroups M, N, or R, and surveys of over 6,500 mainland Indian mtDNA sequences confirmed the absence of these specific mutations, indicating phylogenetic independence driven by genetic drift in small, isolated populations.

Correct option is C

The correct answer is (c) Both (A) and (R) are true, and (R) is the correct explanation of (A)

Explanation:

• Assertion (A) is true: Genetic studies (like Thangaraj et al., 2005) confirm that M31 and M32 are unique to Andaman Tribes.
• They suggest these tribes are descendants of the earliest Paleolithic settlers in South Asia.
• Reason (R) is true and explains (A): The lack of these specific mutations in mainland populations proves genetic isolation.
• Genetic drift in small, isolated groups caused these unique lineages to diverge and be preserved only on the islands.
• This supports the theory that they represent an early offshoot of the Out-of-Africa migration.

• mtDNA (Mitochondrial DNA) is inherited solely from the mother, making it a powerful tool for tracing maternal lineages.
• The Onge and Jarawa are part of the "Negrito" groups of the Andaman Islands.

• Incorrect; the uniqueness of Andamanese DNA is a verified scientific finding.

• Incorrect; the data in R is exactly what provides the scientific basis for the claim in A.

• Incorrect; the sequencing data described in R is the empirical evidence used in these genetic studies.