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.

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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