The recombination frequency between the genes a & c is 5%, b & c is 15%, b & d is 9%, a & b is 20%, c & d is 24% and a & d is 29%. What will be the sequence of these genes on a linear chromosome?
The frequency of recombination between gene pairs on the same chromosome can be used to measure the distance between genes. The distance between two genes is equal to this recombination frequency. If genes are located on the same chromosome, some genes can be very tightly linked hence showed very low recombination and low recombination frequency. If genes are loosely linked, they show higher recombination (high recombination frequency). As the recombination frequency is smallest in case of a and c, it means they are closely located to each other (linked genes). Recombination frequency of a and c is slightly higher but they can also be linked. The recombination frequency of a and d is highest hence the chances are more for these two genes to be located far apart. The correct sequence will be a-c-b-d.
The term - non-mendelian inheritance refers to any pattern of heredity in which features do not separate according to Mendel's laws. These principles describe how features linked with single genes on chromosomes in the nucleus are passed down through generations.
Types of Non-Mendelian Inheritance
Codominance Inheritance
It is a form of incomplete dominance in which both alleles for the same feature are expressed in the heterozygote at the same time. For example, the MN blood types of humans.
Incomplete Dominance
In a heterozygote, the dominant allele does not always completely cover the phenotypic expression of the recessive gene, resulting in an intermediate phenotype which is referred to as "incomplete dominance”.
