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What is an Allele?


Alleles are an important concept in the field of genetics. In basic terms, alleles are variations of a particular gene found on the same place on a chromosome. They are the result of mutations that created slighted altered version of the same gene.  Every individual organism can potentially have two alleles for each gene, one inherited from each parent.


Some people get genes and alleles mixed up. Alleles are different types of genes; if genes were ice cream, alleles would be different flavors of ice cream. 


(Free-Photos, 2017)


So what happens when an organism has two different alleles for the same gene? It depends on how the two alleles interact with each other. Some alleles are dominant over others. For example, if you have one allele for blue eyes and one allele for brown eyes, you will have brown eyes because the brown eye allele is dominant over the recessive blue eye allele.


However, not all genes interact like this. For example, let’s say you breed two flowering plants; one has two alleles for red flowers and the other has two alleles for white flowers. In some cases, all the offspring of this cross would have pink flowers. This is an example of alleles that are co-dominant; if an organism has one copy of each allele their impacts are combined.


One of the first scientists to do experiments with alleles was Gregor Mendel. Mendel is often known as the “father of genetics” for his studies in heredity in pea plants. One of Mendel’s observations was that in pea plants the allele for purple flowers was dominant over the allele for white flowers.


Image Citation:


Free-Photos (photographer). (2015). Eye Blue Eyelashes [photography]. Retrieved from

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