Same principle applies to all sexually reproducing

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Same principle applies to all sexually reproducing organisms. Mendel worked with traits that have dominant and recessive alleles, and follow the rule of independent assortment - the simplest scenario by which genetic information is sexually transmitted. What is a Dominant Gene? Intermediate Inheritance - 14.5.1 >>>>>>The relationship between genotype and phenotype is rarely simple INTERMEDIATE INHERITANCE or incomplete dominance (see fig. 14.10) --- Incomplete dominance >sounds like blending theory but it’s not -recessive trait can still emerge in the F2 -genotype is apparent from phenotype >> Complete dominance to codominance The dominance/recessiveness relationships vary over a continuum. COMPLETE <====== INCOMPLETE ======> CODOMINANCE DOMINANCE DOMINANCE --- Codominance Codominance and Multiple Alleles: ABO Blood Groups - 14.5.2 >>Multiple alleles A gene may have more than two allele forms. ABO blood group is an example of multiple alleles (see table 14.2) BLOOD POSSIBLE ANTIGENS PRESENT ANTIBODIES PRESENT IN
TYPE GENOTYPES ON RBC SERUM A IA IA or IA i A anti-B B IB IB or IB i B anti-A AB IA IB AB None O ii O anti-A and anti-B Epistasis: One Gene Affecting Another - 14.6.1 >>> Epistasis -one gene that changes the expression of another gene. --- Epistasis -Mouse fur coloration(see fig. 14.11) Polygenic Inheritance - 14.7.1 >>> Polygenic inheritance of quantitative characters -multiple loci involved in a single trait. -trait varies in a continue --- Polygenic inheritance -additive effect of two or more genes on a single phenotypic characteristic -contrasted with pleiotropy and epistasis -Skin pigmentation (see fig. 14.12) Pleiotropy: Multiple Phenotypic Effects - 14.7.2 >>> Pleiotropy - genes that affect many traits --- Pleiotropy -Sickle-cell anemia >>>Environmental impact on phenotype A single genotype may product a range of phenotypes in response to environmental factors. The phenotypic range of the norm of reaction for the genotype (see fig. 14.13) --- Norm of reaction

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