Linkage and recombination were first studied in -
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Drosophila
Linkage means that genes lying close together on the same chromosome stay together and do not assort independently. Recombination is the formation of new combinations of genes by crossing over. T. H. Morgan found both while doing dihybrid crosses in the fruit fly Drosophila melanogaster. He saw that two genes did not separate independently and that the F2 ratio was far from 9:3:3:1.
(1) Pisum sativum — Incorrect. This is Mendel’s garden pea. The genes he studied assorted independently, so he found no linkage.
(2) Drosophila — Correct. Morgan’s crosses in this fly showed linkage and recombination.
(3) Zea mays — Incorrect. Maize is not the organism of Morgan’s crosses, in which linkage and recombination were first shown.
(4) Homo sapiens — Incorrect. Humans cannot be crossed in the laboratory. Their inheritance is followed through pedigrees.
NCERT Extract:
Linkage and Recombination –
