BIOL 1103 1st Edition Lecture 15 Outline of Last Lecture II Mendel and His Experiments III Dihybrid Crosses involving Two Characters IV Probability V Reception of Mendel s ideas VI Incomplete Dominance and Co dominance Outline of Current Lecture VII Sex Linkage a Thomas Hunt Morgan VIII Passing Mutant Traits IX X Linked Recessive Disorders X Dominant Disorders Current Lecture Sex linkage o Sex linked genes located on sex chromosomes o 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 o o A carrier female with pass mutation to half her sons and half her daughters o o 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 Russia o 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 carrier o Duchenne Muscular Dystrophy mutation in dystrophin gene and Xchromosome which codes for making proteins Dominant gene disorders o Huntington s disease degeneratin of central nervous system terminal doesn t show until age 30 o 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 nucleus
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