Question

The first animal for which a linkage map constructed, was
A. Neurospora
B. Drosophila
C. Pisum sativum
D. Oenothera

Answer 1

Genetic linkage is the tendency of DNA sequences that are close together on a chromosome to be inherited together during the meiosis phase of sexual reproduction.
A linkage map is also known as a genetic map.
It is a table for a species or experimental population that shows the position of its known genes or genetic markers relative to each other in terms of recombination frequency, rather than a specific physical distance along each chromosome.

Complete answer:
Linkage maps were first developed by Alfred Sturtevant, a student of Thomas Hunt Morgan. Thomas Hunt Morgan's Drosophila melanogaster genetic linkage map was the first successful gene mapping work and provides important evidence for the chromosome theory of inheritance.
The map shows the relative positions of alleles on the second Drosophila chromosome.
The distances between the genes (centimorgans) are equal to the percentages of chromosomal crossover events that occur between different alleles.
A linkage map is a map based on the frequencies of recombination between markers during crossover of homologous chromosomes.

So, the correct answer is “Option B ”.

Note: Genetic linkage maps of each chromosome are made by determining how frequently two markers are passed together from parent to child.
The frequency of this event helps determine the distance between the two DNA sequences on a genetic map. A linkage map is not a physical map (such as a radiation reduced hybrid map) or a gene map.