Question

All genes located on the same chromosome
a. form different groups depending upon their relative distance
b. form one linkage group
c. will not form any linkage groups
d. form interactive groups that affect the phenotype

Answer 1

Hint: The gene is the functional unit of inheritance. It is the physical unit of heredity which is passed on from parents to the offsprings. It is made up of particular nucleotide sequences which are found at specific positions in a given chromosome. The genes are responsible for coding specific proteins.

Complete answer:
The linked genes are grouped together in a chromosome to form the linkage group. This linkage relates to the organism’s genome. Linkage group refers to the group of genes that are present on the same chromosome.

During the events of cell division, the group of linked genes moves together as a unit. These linked genes present on a chromosome are separated only if the gap between them reduces to minimum or when there is crossing over. For instance, as in human beings chromosomes are present in 23 pairs, so there is an occurrence of 23 linkage groups. The genes that are linked together are often inherited together during the cell cycle.

There is no independent movement of these genes that means they are always transmitted in groups. The linkage groups are found on a single chromosome at different locus in conditions when there is no crossing over.

Hence, the correct answer is option (B).

Note: Genetic mapping refers to a process of identifying the location of particular genes in a chromosome. The mapping also helps in determining the recombination frequencies of genes on the basis of the distance between them.