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.
| Refer: Chromosome Structure |
Difference between homologous and Non homologous chromosomes
The table below depicts the important differences between homologous and non homologous chromosomes
| It is the pair of chromosomes with the same sequence of genes. | Chromosomes do not constitute the same pair |
| Both arms of chromosomes and centromeric position are the same | Both lengths of arms of chromosomes and centromeric position vary |
| Alleles are of the same genes present in that same loci | Alleles are of different genes |
| Pairing of homologous chromosomes is brought about in meiosis I | Pairing of non-homologous chromosomes does not take place in meiosis I |
| Chromosomes belong to the same pair of chromosomes comprising paternal and maternal chromosomes | Chromosomes belong to different homologous pairs |
| During recombination, some parts of chromosomes could be exchanged | In translocation, some parts of the chromosome could be exchanged |
| 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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