What is the Difference Between Coupling and Repulsion?

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Coupling and repulsion are two aspects of gene linkages that describe the arrangement of genes on chromosomes and their inheritance patterns. The main differences between coupling and repulsion are:

  1. Arrangement of genes: In coupling, two genes are located on the same chromosome, while in repulsion, the two genes are located on different chromosomes.
  2. Inheritance: In coupling, the genes coming from identical parents enter the same gamete and are inherited together. In repulsion, the genes coming from different parents are separated in different gametes and are inherited separately.
  3. Dominance: Coupling refers to the linkage of two dominant or two recessive alleles, while repulsion refers to the linkage of dominant alleles with recessive alleles.

In summary, coupling and repulsion are two different gene arrangements that influence how genes are inherited. Coupling involves the linkage of genes on the same chromosome, leading to the inheritance of both genes together, while repulsion involves the separation of genes on different chromosomes, leading to the inheritance of each gene separately.

Comparative Table: Coupling vs Repulsion

Coupling and repulsion are two aspects of gene linkages that occur when genes are located close to each other on the same chromosome. Here is a table summarizing the differences between coupling and repulsion:

Feature Coupling Repulsion
Definition Coupling refers to the linkage of two dominant alleles or two recessive alleles of different genes on the same chromosome. Repulsion refers to the linkage of a dominant allele and a recessive allele of different genes on the same chromosome.
Gene Arrangement Two dominant alleles (e.g., AB) or two recessive alleles (e.g., ab) are present on the same chromosome, while the other chromosome carries the remaining recessive or dominant alleles (e.g., ab or AB). A dominant allele and a recessive allele are present on the same chromosome (e.g., Ab/aB), with each allele coming from a different parent.
Diagrammatic Representation Coupling represents a cis arrangement, where the two alleles of interest are on the same chromosome. Repulsion represents a trans arrangement, where each chromosome carries one dominant and one recessive allele of different genes.
Inheritance Coupling occurs when genes for different traits segregate independently of each other, as stated in Mendel's law of independent assortment. Repulsion occurs when genes for different traits do not segregate independently, violating Mendel's law of independent assortment.

In summary, coupling involves the linkage of two dominant or two recessive alleles on the same chromosome, while repulsion involves the linkage of a dominant and a recessive allele on the same chromosome, each coming from a different parent.