BIOLOGY 1M03 Lecture : 1MO3_Chapter 14.docx
11 Jun 2013
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It is very helpful to control parent mating and to separate groups of offspring and grow them in known conditions. In short-lived, model organisms, we can start with lines that are homozygous (also called pure-breeding or true-breeding). Mendel could self them for generations to ensure they were true breeding. Pattern of inheritance consistent with dominant allele at single locus. If gene freq. of pku allele is 0. 001, freq. of babies with pku is 0. 000001. Balanced polymorphism: heterozygous individuals have highest fitness. Many traits influenced by many different genes. Genetic traits should be more similar in monozygotic twins than dizygotic. Sickle-cell anemia: high frequency for s allele in regions with malaria, higher fitness in s allele carriers with malaria. Lactose tolerance: northern europe and northern africa ingle, dominant gene. Non-insulin-dependent-diabetes: genetic basis, nidd would have helped build fat reserves during times of plenty. Crossing over means large sections of dna carried together with selected allele: haplotypes.
