Question

What are linked genes? How can a pair of linked genes be identified?

Answer 1

A gene is a sequence of nucleotides in DNA or RNA which gives the gene product that can be RNA or protein and linked genes are the genes which are together inherited as these genes are physically close to each other on similar chromosomes.

Complete answer:
-Genes that are located on the same chromosomes are called the linked genes. Alleles in the genes segregate to each other at the time of meiosis, unless they are removed by the help of crossing over. Crossing over takes place when two homologous chromosomes start exchanging the genetic material at the time of meiosis.
-If the genes are far apart on a chromosome, or a different chromosome, the recombination frequency in this case is inheritance of alleles of the two loci are independent.
-If the recombination frequency is less than we can say that two loci are linked.
-Linked genes can be identified by the help of crossing male and female. If the number of progenies is more like parents it means that the genes are linked whereas if the number of recombines or non- parental types produced are more in number then genes are not linked.
-The frequency of crossing over in the genes helps in making the linkage maps that give the locations of genes on chromosomes.
-In humans there are X or Y chromosomes found. There are differentfamiliar sex-linked traits mainly haemophilia, red green colour blindness, some high blood pressure genes, Duchenne muscular dystrophy and also fragile X syndrome.
-So the inheritance of individual genes is less when the genes are linked together as genetic linkage and in some species this genetic linkage is given by the genetic map, where it describes the distance of frequent or known genes.
-The only way to know the linked genes was by the mathematical analysis of the relative frequencies of genes in the family groups.

Note: Linked genes are designed each side in the same order it is always ab/ba. The protocols that genes are written in the similar order provides the geneticists to use a less variation in which the wild type allele is written with a plus sign only.