The main difference between allele and locus is, alleles are variants of the gene and they occur on the same place of the chromosome. Location of chromosome where the gene is found is called a locus. Allele differ from each other in every other gene and this difference results in different properties or traits. But at times, different alleles can produce same effect as well. Allelic issues can cause genetic anomalies at times.
What is Allele?
DNA is sequenced in more than one way and among one of those ways is allele. In each gene, allele differ from other allele and thus, every allele is different. Color of two organisms could be different due to expression of different alleles on the genes. Traits and properties could be different due to difference in alleles but some alleles are capable of producing the same effect. Alleles are different version of phenotype, lie the color of an eye could be black, brown, green, blue or any other. There are multiple alleles and could be found on at the locus. An organism have two alleles for each gene because allele is a point on chromosome, which is fixed. And as those chromosomes occur in pairs, there are two alleles for one gene only.
What is Locus?
Locus is that point on chromosome where the trait or gene is situated. Gene is found at a certain locus. Homologous chromosomes have same genes at the same locus but have different alleles. Gene mapping is used very commonly to determine locus in a certain biological trait. Hence, locus is a maker of DNA. Locus is usually referred as a chromosome marker. It could be called as a gene but it is used specifically to locate the position of chromosome on the gene. Single allele can be found on one single loci and that is what makes it distinct.
Key Differences between Allele and Locus
- Allele is a specific variation of gene while locus is that point on a chromosome which contains the gene.
- Allele is responsible for different traits like blue, green, brown or black eyes, while locus is not.
- Allele is a sequence of DNA but locus serves as a marker.
- Locus is used specifically to locate the position of chromosome on a gene.
- More than one allele can be found on a single locus but not the other way around.
- An organism have two alleles for each gene because chromosomes occur in pairs.