B311D080123 • Effects of multiple alleles or codominance • More than one gene locus; dihybrid cross • Interacting effects on phenotype •--A clarification of my Bio Questions and Answers email yesterday for learning objective 10, each gamete has 24 chromosomes •-- New handout in the back of the room •--Old handouts are on the front table •--Homework one assignment is due tonight •--Homework two assignment will be posted on Blackboard Now we will talk about inheritance patterns of dominance and the relationships between genotype (alleles present) and phenotype (trait appearance.) This is by the way of simple dominance, incomplete dominance, and co dominance. Some triplet repeat disorders show pattern of a dominant trait. Triplet repeat disorders like fragile X and Huntington's disease are some example. If we have some genes where in the coding region of the gene, we have a repeat. In a normal allele, there would be forty repeats, in example, in the coding region. But if more mutations occur, we end up with an extended number of triplet repeats, thus the beginning of the mutation, where there are 55 to 200 repeats of CGG repeats. In studying families with this, in several populations, the number of repeats
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