BIOSC 150 1nd Edition Lecture 20 Outline of Last Lecture I Meiosis I II Meiosis II III Sexual Reproduction Outline of Current Lecture 1 Non mendelian 2 Human Genetics Current Lecture Meiosis making haploid gametes Independent assortment occurs in Meiosis I Different genes traits are on different chromosomes This in turn affects the phenotypic ratios of F1 and F2 generations the ratios become closer Recombination evidence is seen with microscopy and confirmed with allele mapping or DNA sequencing Recombination holds homologues together paired Frequency of recombinant offspring correlated directly with the distance between two genes 19 6 recombinant offspring for example translates to 19 6 map units Non mendelian genetics Linked genes do not sort 9 3 3 1 Linked genes tend to be inherited together and do not sort independently into gametes Most genes have multiple alleles Most traits are controlled by many genes Example Wheat kernel color is a quantitative trait These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Wheat kernel color is controlled by at least three genes Most traits are controlled by genes and environment With environment referring to age size diet medications area etc Twin Study Fraternal Twins 50 genetic similarity same environment Identical Twins 100 genetic similarity same environment Low Heritability phenotype has the same chances of occurring in identical and fraternal twins High Heritability phenotype is more likely to occur in identical twins due to inherited factors The heritability estimate for height is very high vs The heritability estimate for Parkinson s disease is very low The human diploid genome is 3 billion x2 nucleotides
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