Difference between Homologous and Non-homologous chromosomes

The primary difference between these two chromosomes – homologous and non-homologous lies in their constituency of alleles. Homologous chromosomes consist of alleles of the same gene type found in the same loci unlike non-homologous chromosomes, which constitute alleles of varying gene types.

What are Homologous and Non-homologous Chromosomes?

In the nucleus, chromosomes provide a structure to the genetic content of a specific cell. On the basis of the pattern of pairing during the meiosis (metaphase 1), chromosomes can be distinguished into homologous chromosomes and non-homologous chromosomes.
 
Homologous chromosomes correspond to the chromosomes present on the same pair in contrast to non-homologous chromosomes where they are found on different pairs. Number of chromosomes in homologous pairs are based on the ploidy of that entity.

Difference between homologous and Non homologous chromosomes

The table below depicts the important differences between homologous and non homologous chromosomes

Homologous Chromosomes
Non-homologous chromosomes
What it means
It is the pair of chromosomes with the same sequence of genes. Chromosomes do not constitute the same pair
Structure
Both arms of chromosomes and centromeric position are the same Both lengths of arms of chromosomes and centromeric position vary
Allele type
Alleles are of the same genes present in that same loci Alleles are of different genes
Pattern of pairing
Pairing of homologous chromosomes is brought about in meiosis I Pairing of non-homologous chromosomes does not take place in meiosis I
Importance
Chromosomes belong to the same pair of chromosomes comprising paternal and maternal chromosomes Chromosomes belong to different homologous pairs
Outcome
During recombination, some parts of chromosomes could be exchanged In translocation, some parts of the chromosome could be exchanged
Example
In humans, 22 autosomal chromosomes are examples of homologous chromosomes. XX sex chromosomes are an example too Examples of non-homologous chromosomes are X and Y chromosomes

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Frequently Asked Questions

What is the difference between homomorphic and heteromorphic chromosomes?

A homologous pair of chromosomes that do not differ morphologically are referred to as homomorphic chromosomes, whereas heteromorphic chromosomes are the homologous chromosomes that differ morphologically, for example X and Y chromosomes.

What happens if non-homologous chromosomes crossover?

Non-homologous crossover is a rare event but when it happens it causes deletion or insertion of genetic material in the chromosomes.

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