Concept 20 - Concept14. Inthe20thcentury, inheritancemore Infact,

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Concept 14.3 Inheritance patterns are often more complex than predicted by simple Mendelian genetics. In the 20th century, geneticists extended Mendelian principles both to diverse organisms and to patterns of  inheritance more complex than Mendel described. In fact, Mendel had the good fortune to choose a system that was relatively simple genetically. o Each character that Mendel studied is controlled by a single gene. o Each gene has only two alleles, one of which is completely dominant to the other. The heterozygous F offspring of Mendel’s crosses always looked like one of the parental varieties because one  allele was dominant to the other. The relationship between genotype and phenotype is rarely so simple. Extending Mendelian Genetics for a Single Gene The inheritance of characters determined by a single gene deviates from simple Mendelian patterns when alleles  are not completely dominant or recessive, when a gene has more than two alleles, or when a gene produces multiple phenotypes. We will consider each of these situations. Degrees of Dominance Alleles show different degrees of dominance and recessiveness in relation to each other. One extreme is the 
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This note was uploaded on 01/04/2012 for the course BSC BSC1005 taught by Professor Orlando,rebecca during the Fall '10 term at Broward College.

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Concept 20 - Concept14. Inthe20thcentury, inheritancemore Infact,

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