Multiple allele
- 1. Multiple allele Harshraj Subhash Shinde KKW, CABT, NASHIK
- 2. Outline • Introduction and Defination • Features of Multiple allele • Examples of Multiple allele a. Blood group in human being b. Coat colour in mice
- 3. Introduction “Multiple allele- When more than two different form of given gene exist in a species they are called as multiple allele” • Normally individual has two alleles • During his study on Genetic Mendel also assumed only two alleles of one trait. • There can be large number of possible allelic forms in that same population. This situation is called as multiple allelism.
- 4. Features of Multiple Alleles Multiple alleles always occupy the same locus on the chromosome. Multiple alleles always influence the same character. No crossing over among the member alleles of the same multiple allelic series.
- 5. Examples of Multiple Alleles a) Blood group (ABO) in human. b) Coat color in mice. c) Coat color in rabbit. d) Eye color in Drosophila.
- 6. Blood group (ABO) in human • Classical and most common example of multiple allele is ABO blood group of human being • Gene coding blood group has three alleles rather than two. • For the ABO gene, the three alleles are the IA, IB and i alleles. We typically call these alleles "A," "B," and "O," • “letter "I,“ stands for "immunoglobin."
- 7. Cont… • The IA and IB show co-dominance - an individual who is heterozygous for these two alleles, the phenotypes of both alleles are completely expressed, thus producing blood type AB. • The i allele (the "O" allele) is recessive to both the IA and IB alleles (the "A" and "B" alleles). Sr.no Genotype Phenotype 1 IAIA or IAi Type A 2 IBIB or IBi Type B 3 IAIB Type AB 4 ii Type O
- 8. Coat color in Mice • The coat or hair color in mice is determined by a single gene with a series of alleles. • Alleles for black, brown, agouti, gray, albino, and other colors of hair. • These alleles follow order of dominance like agouti > black > albino. • This means that agouti is dominant to black and albino; black is dominant to albino.