Mendels concept of inheritance envisaged alternative forms of same gene or factor. This would mean that each gene had two alternative forms or allelomorphs, one being dominant or partially dominant and the other recessive; one being wild form and the other mutant. If the mutant form developed from wild form due to mutation, there is no reason, why we should not expect that the wild form can mutate in more than one ways. The mutant form can also mutate once again to give rise to another mutant form. Therefore, a gene can have more than two allelomorphs. These allelomorphs make a series ef multiple alleles. Relationship between different alleles may or may not be a simple dominant-recessive relationship, but they are usually characterized by their location on the same locus, and therefore, by lack of crossing over between them. However, discovery of pseudoalleles has rendered this definition out of date, that multiple alleles, can occupy different sites within a gene and that crossing over between them can take place... Read more... biocyclopedia/index/genetics/multiple_alleles_based_on_classical_concept_of_allelomorphism/multiple_alleles_and_isoalleles.php
Posted on: Mon, 18 Nov 2013 05:15:39 +0000
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