BIOSC 150 1nd Edition Lecture 20Outline of Last Lecture I. Meiosis III. Meiosis IIIII. Sexual ReproductionOutline of Current Lecture 1. Non-mendelian2. Human GeneticsCurrent LectureMeiosis- 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 sequencingRecombination- 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 unitsNon-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 environmentLow Heritability= phenotype has the same chances of occurring in identical and fraternal twinsHigh 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
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