Biology

Difference between Linkage and Crossing Over

Main difference

The main difference between linking and crossing is that linking certifies genes on the same chromosome that are inherited together, while crossing ensures the separation of genes and separates them into different gametes that are present on the same chromosome.

Bonding vs. crossover

The distance between two genes on the same chromosome is inversely proportional to the point of attachment, while the distance between two genes on the same chromosome is directly proportional to the possibility of crossover. The function of the link is that the genes present on the same chromosome are inherited together at the same time and in the same position; on the other hand, the role of crossover is to ensure the separation of genes present on the same chromosome and to exchange genes between two homologous chromosomes.

In bonding, it ensures the conservation of parental traits in their offspring and the next generations by inheriting them; on the contrary, when crossing, it causes the diverse changes in the parental traits in its next generations and does not preserve the traits of its parents in its offspring. The main disadvantage of bonding is age, which decreases bonding with increasing age; on the other hand, the crossover tends to increase with increasing age.

Linkage generally decreases the possibility of variations in the next generation by inheriting the same genes in generations from their parents; does not play a role in variation by keeping the same genes, while crossing plays an important role in variations in the next generation by inheriting different genes from parents in their offspring.

Linkage tends to occur when two different genes are generally closer to each other on the same chromosome, while crossover tends to occur when two different genes are generally present widely separated from each other on the same chromosome. Furthermore, clusters of genes are formed at the link, whereas crossover normally disrupts clusters of genes by separating them and exchanging them into different genera.

The linkage inherits the same genes, whereas the crossing only occurs during the prophase process of meiosis 1. The linkage does not produce recombinant alleles; conversely, crossing generally tends to produce recombinant alleles.

Comparative chart

Link Crossing
The link generally mentions the tendency of DNA sequencing to stick together in the next generation inheriting the same genes. Crossover generally refers to the exchange of gene segments between two non-sister chromatids of homologous chromosomes, resulting in non-identical chromatids.
Distance between two genes
Inversely proportional to the attachment point Directly proportional to the fact of crossing
Meaning
To ensure that genes on the same chromosome are inherited together at the same time and in the same position to ensure the separation of genes present on the same chromosome and exchange genes between two homologous chromosomes
Maintenance of parental traits
It ensures the conservation of parental traits in their offspring and the next generations by inheriting them. It causes the various changes in parental traits in its next generations and does not preserve the traits of its parents in its offspring.
Influence of the era
It tends to decrease with increasing age. It tends to increase with increasing age.
Variations
It generally decreases the possibility of variations in the next generation by inheriting the same genes in generations from their parents, so it does not play a role in the variation by keeping the same genes. It plays an important role in the variations in the next generation by inheriting different genes from the parents in their offspring.
Idea
It occurs when two different genes are generally closer to each other on the same chromosome It occurs when two different genes are usually present widely separated from each other on the same chromosome
Gene clusters
The gene clusters are made It normally disrupts gene clusters by separating them and swapping them into different genes.
Happens
Inherit the same genes It only occurs during the prophase process of meiosis 1
Recombinant alleles
Does not produce recombinant alleles Generally, it tends to produce recombinant alleles.

What is a link?

The term linkage has a broad meaning, which generally refers to the tendency of DNA sequencing to stay together in the next generation inheriting the same genes. Linkage is the study of the inheritance of all the genes that are present together on the specific chromosome. The linkage group, which is generally the same as the chromosome, is formed when genes are inherited together called linked genes from the parents on the specific chromosome.

The total number of linkage groups generally equals their haploid chromosome number. The chromosome has several genes and they are all inherited together. Due to the link, genes are inherited together during the production of gametes present on the same chromosome.

Linkage usually occurs between genes that are located very close to each other on the same chromosome, but genes that are present widely separated from each other on the chromosome are partially linked, which means that closer genes are stronger than genes that are they are present. far away from each other. Ligation does not produce recombinant alleles.

Therefore, genes that are present far away can easily be separated during the recombination period. Genes that are present on different chromosomes cannot normally be linked, and an independent variety can be seen on these chromosomes at the dihybrid junction. The scientist TH Morgan carried out a series of experiments with the house fly (Drosophila) and showed that two genes are present in the pair of chromosomes in the coupling phase (cis) or repulsion phase (trans).

This whole phenomenon was called linkage and the genes were called linked genes. The numbers of the linkage groups vary in each organism, as the linkage group in man is 23 when coinciding with the number of chromosomes n = 23. The linkage group of Drosophila is 4.

What is Crossing Over?

The term “crossover” can be understood as generally referring to the exchange of gene segments between two non-sister chromatids of homologous chromosomes, resulting in non-identical chromatids. Therefore, crossover can also be described as the tendency of genes that are present on the same chromosome to isolate and from each other in different gametes.

Therefore, the crossing overlaps a role that facilitates genetic recombination to produce a new combination of alleles by exchanging their segments. Also, crossover tends to occur at the synapse, which is the tight bond that generally holds the two homologous chromosomes to each other. Crossover only occurs during the prophase process of meiosis 1.

The crossing has its main advantage in the variations and the origin of new characters in the next generations, which also leads to genetic variations. But the fault in the crossing is that it causes various changes in parental traits in its next generations and does not preserve the traits of its parents in its offspring.

Key differences

  1. Linkage causes the inheritance of genes that occur together and are present on the same chromosome; on the other hand, the crossing causes the separation of genes that are present in the same chromosome.
  2. There is a reciprocal link between the distance and the junction point generally present between two genes on the same chromosome, while there is a direct relationship between the distance and the possibility of crossover between two genes on the same chromosome.
  3. The bond ensures the preservation of the characteristics of the parents in their offspring; on the contrary, the cross generally does not preserve the characteristics of its parents in its offspring.
  4. With increasing age, the bonding process slows down; on the other hand, with increasing age, the crossing process tends to increase.
  5. The possibility of variations in the next generation is lower in the linking process by inheriting the same genes, while the possibilities of variations in the next generation are greater in the crossing of the process inheriting the different genes.
  6. Linkage generally occurs when the distance between two different genes is very small on the same chromosome, while crossover occurs when the distance between two different genes is very large on the same chromosome.
  7. Linking produces clusters of genes whereas crossing normally disperses clusters of genes.
  8. The link conveys the same traits, while the crossover occurs only during prophase of meiosis 1.
  9. The link does not usually imply the recombinant frequency; conversely, crossover generally involves recombinant frequency.

Final Thought

The above discussion concludes that linking certifies genes on the same chromosome that are inherited together and preserve parental traits, while crossover ensures gene separation and separates them into different gametes that are present on homologous chromosomes and causes variations. . in genes of the next generation.

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