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Polygenic inheritance

Polygenic inheritance - Gene linkage A chromosome has many...

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Polygenic inheritance Although many characteristics are determined by alleles at a single place on the chromosome, some  characteristics are determined by an interaction of genes on several chromosomes or at several  places on one chromosome. This condition is  polygenic inheritance.   An example of polygenic inheritance is human skin color. Genes for skin color are located in many  places, and skin color is determined by which genes are present at these multiple locations. A  person with many genes for dark skin will have very dark skin color, and a person with multiple  genes for light skin will have very light skin color. Many people have some genes for light skin and  some for dark skin, which explains why so many variations of skin color exist. Height is another  characteristic probably reflecting polygenic characteristics.
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Unformatted text preview: Gene linkage A chromosome has many thousands of genes; there are an estimated 100,000 genes in the human genome. Inheritance involves the transfer of chromosomes from parent to offspring through meiosis and sexual reproduction. It is common for a large number of genes to be inherited together if they are located on the same chromosome. Genes that are inherited together are said to form a linkage group. The concept of transfer of a linkage group is gene linkage. Gene linkage can show how close two or more genes are to one another on a chromosome. The closer the genes are to each other, the higher the probability that they will be inherited together. Crossing over occurs during meiosis, but genes that are close to each other tend to remain together during crossing over....
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