BIOL 1103 1st Edition Lecture 15Outline of Last Lecture II. Mendel and His ExperimentsIII. Dihybrid Crosses involving Two CharactersIV. Probability V. Reception of Mendel’s ideasVI. Incomplete Dominance and Co-dominanceOutline of Current Lecture VII. Sex Linkagea. Thomas Hunt MorganVIII. Passing Mutant TraitsIX. X-Linked Recessive DisordersX. Dominant DisordersCurrent Lecture- Sex linkage:o Sex-linked = genes located on sex chromosomeso Thomas Hunt Morgan = 1910 – Columbia University - was the first scientist to associate a specific gene with a specific chromosome Experimented with fruit flies with white eyes as opposed to the typical fruit fly with red eyes- Passing traits:o Father with a certain trait will transmit mutant allele to all daughters and no sons: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.oo A carrier female with pass mutation to half her sons and half her daughters:oo If a carrier mates with a male with the trait, there is a 50% chance that each child born to them will have the trait, regardless of sex:o- Recessive disorders:o Hemophilia = lack of one or more clotting factors of blood Queen Victoria was carrier of hemophilia which transferred all the way down to Nicholas II of Russiao Red-green color blindness = far more common in males; for female to be color blind, father has to be color blind and mother has to be carriero Duchenne Muscular Dystrophy = mutation in dystrophin gene and X-chromosome which codes for making proteins- Dominant gene disorders:o Huntington’s disease = degeneratin of central nervous system, terminal, doesn’t show until age 30o Achondroplasia = dwarfism; defective protein called “fibroplast growth racter receptor” o Polydactylism = six fingers- Abnormal chromosomal numbers can cause things like Down Syndrome (extra chromosome), Klinefelter’s syndrome (extra X-chrom.), super male (extra Y)- As a mother’s age increases, so do her risks of having a child with Down Syndrome- Barr body = inactivate X-chromosome in females because they only need the genes of one chromosome; in
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