Essay On Polygenic Inheritance

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Polygenic inheritance describes the inheritance of polygenic traits. A polygenic trait is a trait determined by more than one gene. Polygenic traits also have many possible phenotypes that are determined by the interactions among these several alleles. This type of inheritance is in contrast with Mendelian inheritance where traits are determined by only one gene (Monogenic trait). In Mendelian inheritance, the monogenic trait exhibits complete dominance and in polygenic inheritance, the polygenic trait exhibits incomplete dominance. Incomplete dominance means that the genes contributing to a trait have equal influence and the alleles for the gene have an additive effect and therefore one allele doesn’t mask or dominate another. The phenotype…show more content…
Their blood therefore will not normally be rejected when it is given to others with different ABO types (universal donors). This also means they can only receive type O blood themselves. It is also evident from the table that those who have type AB blood do not make any ABO antibodies. Their blood does not discriminate against any other ABO type (universal receivers). This also means that their blood cannot be given to people with any other type because they produce both kinds of antigens. (O'Neil, n.d.)
In 1910 and 1911, research by Ludwik Hirszfeld and Emil von Dungern was carried out in Germany which showed that the ABO blood types are hereditary. Now we know that they are determined by genes on chromosome 9, and that they are not affected by environmental influences during life. A person’s ABO type results from the inheritance of 1 of 3 alleles (A, B, or O) from each parent. (O'Neil, n.d.)
Genetic Combinations of ABO Blood Groups:
Parent
Alleles
The inheritance of ABO blood types doesn’t always follow such simple rules of inheritance. This is due to the fact that a third antigen (H) on the surface of red cells can prevent the expected ABO blood type from occurring. (O'Neil,

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