BIOL 240 1st Edition Lecture 12Outline of Last Lecture I. Chromosome mappingII. Procedure for mapping crossesOutline of Current Lecture I. Cystic FibrosisII. Single Nucleotide PolymorphismsIII. Chromosome RearrangementsCurrent LectureI. Cystic Fibrosis- Most common recessive lethal inherited syndrome (1/2500)- Carriers are very common: 1 in 30- Caused by recessive mutation on chromosome 7- Gene discovered by combining recombination mapping and DNA cloningII. Single Nucleotide Polymorphisms- Homologous chromosomes differ at a single nucleotide- Once every 500-1000 base pairs- Fairly common; make useful molecular markers for mappingIII. Chromosome Rearrangements- Deletion: when a gene is deleted completelyo Chromosome breaks are driven by radiation and certain chemicals. Inaccurate repair is the origin of many rearrangements.o “deletion loop”: to pair with a deletion bearing homolog, the normal homolog must loop out the unpaired DNAo Example: cri du chat syndrome—result of deletion of the end of chromosome 5; also Williams syndrome—deletion of 17 genes- Duplication: when a gene or genes are duplicated- Inversion: when the order of the genes gets mixed up- Nonreciprocal translocation: when a part of the gene sequence on one homolog gets placed on another homolog (nonhomologous chromosomes)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.- Reciprocal translocation: when a part of the gene sequence on homolog 1 is exchanged for a part of the gene sequence on homolog 2
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