GATE 2019 BT – Question 40

Genetics, Cellular and Molecular Biology · Genetics: Mendelian inheritance, gene interaction, complementation, linkage, recombination, chromosome mapping, extrachromosomal inheritance · 2 marks · Multiple choice

What is encoded by the ABO blood-group locus in the human genome?

Acyltransferase
Galactosyltransferase
Transposase
β-Galactosidase

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Correct answer: (B) Galactosyltransferase

Explanation

The ABO locus encodes glycosyltransferase variants that alter terminal sugars on the H antigen. The B allele’s enzyme transfers galactose, matching the listed galactosyltransferase choice B. The A variant transfers N-acetylgalactosamine; the answer is the intended carbohydrate-transferase class, not a degradative galactosidase.

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