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Blackwell Publishing

Molecular and Mendelian Genetics - What are the laws of heredity?

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Mendel's Second Law

Also known as the principle of independent assortment, Mendel's Second Law holds that genes are inherited independently of each other.

Mendelism is an atomistic theory of heredity. Not only are there discrete genes that encode discrete proteins, but also the genes are preserved during development and passed on unaltered to the next generation.

Mendel demonstrated that an organism inherits an allele from each of its two parents this is the law of segregation. The phenotypes of mothers and fathers often appear to blend in their offspring, and consequently most students of heredity before Mendel thought that inheritance involved some sort of blending of genes. In fact, the underlying genes are preserved.

Figure: (a) blending heredity. The parental genes for blue (A ) and red (a ) color blend in their offspring. (b) Mendelian heredity. The genes are passed on unaltered by the offspring.

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