Difference Between Homozygous and Heterozygous
Main difference
In sexual reproduction, genes inherited from the parents’ chromosomes are responsible for certain traits and characteristics of an individual. In eukaryotic organisms, like humans, the individual has the diploid genetic situation, since it is part of two sets of genes, one of which is known as the maternal gene and is taken from the mother. While the other gene is known as the paternal gene and is taken from the father. The twin copies and combinations of genes known as alleles. The contrast in the alleles of an individual defines both the terms, homozygous and heterozygous. When an individual has two copies of the same allele (for example, MM or mm), then the genetic condition is called homozygous, on the other hand, when an individual has two different types of alleles,
Comparison chart
| homozygous | heterozygous | |
| Definition | When an individual has both copies of the similar allele, the genetic condition is called homozygous. | When an individual has two different types of alleles, then the genetic condition is called heterozygous. |
| alleles | A homozygous individual can carry both dominant and recessive alleles at the same time. | The heterozygous individual carries the dominant and recessive alleles at the same time. |
| gametes | The homozygous individual produces one type of gamete. | The heterozygous individual produces two types of gametes. |
| Example | For example, the dominant allele is denoted as ‘M’, then in homozygotes the parents give up the similar allele of the individual’s genotype, in this case it would be ‘MM’. | For example, the recessive gene is denoted ‘t’ and the dominant gene is denoted ‘T’, then the heterozygous gene condition will also be ‘Tt’. |
What is homozygous?
When the paternal and maternal gene are combined in such a way as to give an individual the two copies of the similar allele, then such a genetic condition is called homozygous. In this type of genetic condition where the rise to a similar type of homozygous individual is given. Similar alleles that establish this condition ensure purity in the transfer of certain traits and characteristics. The individual formed with this type of genetic situation; a homozygous individual can carry dominant or recessive alleles at the same time. Dominant and recessive are the two types of alleles, of which the dominant allele is responsible for the trait that the offspring of the parents will display. For example, the dominant allele is denoted as ‘M’, then in the homozygous the parents give up the similar allele of the individual’s genotype, in this case, would be ‘MM’. And if the traits of both the mother and the father were recessive and the recessive traits are denoted by ‘then in case the homozygous genotype formed is ‘mm’.
What is heterozygous?
When the paternal and maternal gene from the parents are combined in such a way that it consists of two different types of alleles, then such a genetic condition is called heterozygous. As carriers of different alleles, the heterozygous genotype consists of dominant and recessive alleles at the same time. Next, the heterozygous individual produces two types of gametes. Heterozygous gene condition is the combination of recessive gene and dominant gene. Of them, the dominant genes are expressed as a phenotype, and it indicates what additional trait the child will have. The dominant gene can come from the paternal genes or from the maternal genes, although it ultimately expresses the trait in a child. For example, the recessive gene is denoted as ‘t’ and the dominant gene is denoted as ‘T’,
Comparison chart
- When an individual has the two copies of the similar allele, said genetic condition is called homozygous, while when an individual has two different types of alleles, said genetic condition is called heterozygous.
- A homozygous individual can carry dominant or recessive alleles at the same time, on the other hand, a heterozygous individual carries the dominant and recessive alleles at the same time.
- The homozygous individual produces one type of gamete while the heterozygous individual produces two types of gametes.