Are Chromosomes in Pairs: 7 Facts You Should Know

In this article we are focusing on the topic “Are Chromosomes in Pairs: 7 Facts You Should Know”, enlisting all the facts and statements supporting it.

All living cells contains chromosomes which are present in a pair of 23. Somatic cells contain equal number of chromosomes which is 46 (a pair of 23 chromosomes).  Out of 23 pairs, the 22 pairs are autosomes that are same in both males and females, while the 23rd pair is known as the gender chromosome, ‘XX’ in females “XY’ in males, that defines the gender of an infant.

The chromosome pair 23rd is different in males and females, it plays a huge role in defining the gender of the infant. Females contain two copies of X chromosome and the males posses X and Y chromosomes. The autosomes which are 22 in number are generated numerically based on their size, the analysis of chromosomes based on their number and size is known as Karyotyping.

Are Chromosomes single or double in pairs?

are chromosomes in pairs
A male human Karyotype Image from Wikipedia

Yes, chromosomes in humans, plants and animals are present in homologous pair of two, 23 chromosomes in each pair making a total of 46 chromosomes in the nucleus of all the somatic cells. There can be a gain or loss of chromosomes a condition called ‘aneuploidy’, the most common one is “trisomy”.

Trisomy is a condition when there is an extra chromosome found in the cells, the disorder associated with this condition is Down syndrome, where a total of 47 chromosomes are present instead of 46, they can be arranged as ‘XXY’, ‘XYY’ and ‘XXX’.

Are Chromosomes always in pairs?

All the chromosomes in plants, animals and humans always in pairs present inside the cell nucleus. In humans, the female child contains two homologous ‘XX’ chromosomes and the male child has two ‘XY’ chromosomes which are not homologous.

Why are Chromosomes in pairs?

A chromosome is a packaged form of long double stranded deoxyribonucleic acid present in the nucleus wrapped around a histone protein. All organism contains chromosome differing in the size and their numbers, without the chromosome packaging it would be difficult for a cell to hold the lengthy DNA.

A single chromosome is inherited from both parents that is 23 chromosomes from the egg and 23 from the sperm that forms a diploid cell containing 46 number of chromosomes. This cell makes up an entire organism by decoding the hereditary information present in the DNA

How many pairs of Chromosomes are there?

There are 23 pairs of chromosomes in every normal cell in humans, which is a total of 46. Out of 23, 22 of these pairs are known as autosomal chromosomes which are almost equally same in both males and females. The twenty-third chromosome is the one that makes the difference between the male and the female.

What is it called when Chromosomes form a pair?

When chromosomes form a pair, they are known as Homologous chromosomes, which are formed with almost of the length, centromere positioning and the pattern of staining. One chromosome in the pair is inherited from the paternal chromosome and other from the maternal so the genes from both sides are passed on together to the next generation.

Chromosome pairs examples?

There are two special chromosomes or genes that are not homologous to each other but are of great significance, these are ‘X’ and ‘Y’ chromosomes. Females are born with a pair of ‘XX’ chromosomes while the males are born with ‘XY’ chromosomes, both forms a total of 46.

Examples of chromosome pairs in animals; Fruit fly contains 4 chromosome pairs, 12 pairs in a Rice plant and a Dog has 39 pairs of chromosomes, Mosquito contain 6 pairs of chromosomes, frogs have 26 chromosomes and a shrimp contains 508 number of chromosomes.


To conclude the article, we can say that chromosome exist in pairs, one of which is inherited from father and the other from maternal chromosome, only the gender cells contain 23 chromosome and called a Haploid cell until it fuses with the egg cell or a sperm.  

Sneha Sah

Hey! I am Sneha Sah, I have completed post graduation in Biotechnology. Science has always been fascinating to me and writing is my passion. As an academic writer my aim is to make Science easy and simple to learn and read. Reach me at-

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