Tuesday 20 January 2015

Basic Genetic




Happy new year 2015, every one !


I would like to share some common questions on Genetics.

            The first question, what is allele ?
Allele is one of two or more alternative forms of a gene which are usually recognizable by genotypes. These alleles are located in the locus of chromosome. 

           The second question, what is haploid? and what about Diploid ?
Haploid is a cell that contain half as many chromosomes or one set chromosome, as somatic cells. Usually it is symbolized as (n). While Diploid is a cell, tissue, or organism that contain two genomes or chromosome sets. Usually it is symbolized as (2n).  

The third question, how those three component related ?
Those three component linked each other in the Law of Segregation, which proposed by Mendel. The law states that unit of hereditary characters occur in pairs, consist of two or more allele, and that in the formation of gametes are going to segregate so that only one member of the pair goes into a particular gamete. It is a matter  of chance whether a particular gamete gets the dominant or the recessive allele. When the male and female gametes, which the set chromosome is haploid, fuse during fertilization to form zygote, the diploid number is restored.
 In some microorganisms, the major portion of the life cycle is in the haploid stage. They become diploid during sexual conjugation, which is immediately followed by meiosis and the consequent formation of new haploid clones. Phenotypically, each allele is not masked by an allelic mate and segregation between genes give different phenotypic ratio from those in diploid organism.

Source : Ramirez, D.A. 1991. Genetics 7th  Ed. University of The Philippines. Los Banos.