Types Of Genotype
Homozygous organisms have a lower suitability compared to more heterozygous ones, and are subject to natural selection. The number and variety of types of genotype are important characteristics of viability of populations and their changes over time.
Type of genotype and blood group connection
It is established that four groups of human blood are stipulated by the inheritance of three alleles of a single gene (Ja, Jb, i). Thus I(0) group is stipulated by a recessive allele (i) which is dominated by the as allele Ja, defining group II, and allele B, which depends on group III. Alleles Ja and Jb in the heterozygotes determine IV group, that is, where there is a codominance. Thus:
I blood type happens only with genotype ii;
II — with genotypes Ja, Ja and Jai;
III — when genotypes Jb, Jb and Jbi;
IV – with genotype Ja, Jb.
The principle of inheritance of blood group is used for concealed cases of forensic examination in order to exclude paternity. It is necessary to remember the following. By blood it is impossible to establish that this man is the father of the child. We can only say, if he could be the father of the child or paternity is excluded.
Genotype is a holistic system, where all genes interact with each other, influence each other and form a specific phenotype. Therefore, each gene display depends on its genetic environment. Genes in the genotype may be:
• Epistatic – suppressing the effects of other nonallelic genes;
• Hypostatic – suppressing the genes of another allelic pair;
• Pleiotropic genes – can affect the display of multiple characteristics simultaneously;
• Lethal genes – those that reduce the viability of the embryo, even to his death;
• Sub-lethal genes – significantly reduce the viability of the individual, cause death before the beginning of the reproductive period;
• Modifiers – alter the display of another gene; mutator – those that dramatically change some of the characteristics of the organism.