33_printout - Genes & Chromosomes Lecture 33...

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Unformatted text preview: Genes & Chromosomes Lecture 33 (3/30/11) Genes & Chromosomes Reading assignment: pp. 317, 322 ­325, 947 ­954. Problems: N&C ch. 9, #9 (don’t spend too much Kme figuring out exact answer, just think about overall process), ch. 24, #4. SG p. 306, #2,5 Samples loaded at this end A C G T • expose x ­ray film • transfer to membrane • isolate DNA • denature DNA • collect evidence • cut with restricKon enzyme • hybridize to radioacKve probe • run gel 5’ _____ _____ _____ _____ _____ _____ _____ _____ _____ 3’ 1 Genes & Chromosomes 2 Genes & Chromosomes NIH: SystemaKc approach Celera: Whole genome shotgun approach Director of NIH MulK ­billionaire (founder of Celera Genomics, InsKtute of Genomic Res, Craig Venter Inst.) 3 Genes & Chromosomes Shotgun versus systema4c Requires >10x coverage to sequence 90 % of genome. Possible only if cost of sequencing is low and computer sodware is sophisKcated. Labor intensive step The most challenging task in the genome project was not in finding all the pieces of Humpty The challenge was how to put Humpty together again 4 Genes & Chromosomes The history of genome sequencing 2010 >$10/base $1/base ~1c/base ~1c/10 b Ordering of the clones in a DNA library using STS (sequence tagged sites) or EST (expression sequence tag) 100 ­300kb STS sequence-tagged sites } contigs 5 Genes & Chromosomes 6 Genes & Chromosomes 7 Genes & Chromosomes Comparative genomics of Mice and Men • The mouse genome is ~97.5 % identical to the human genome • Of ~30,000 genes, only about 300 genes are unique to either organism. 99% of mouse genes have homologues in humans! Man Mouse What makes mice and men different? •  unique genes likely to confer traits unique to each of these organisms • related genes are similar (up to 70 ­90%) but not iden4cal. Related genes may have different structures and their protein products may have different ac4vi4es. Examples of human inherited diseases that result from a single nucleo4de change. • A gene can produce more than one protein product through alterna4ve splicing and posMransla4onal modifica4ons. •  Duplicated genes may evolve to acquire new func4ons unique to each organism. • A gene can produce more or less protein in different cells at various 4mes in response to developmental or environmental cues, and many proteins can express disparate func4ons in various biological contexts. More importantly, there is significant divergence in the noncoding sequences of mice and men! 8 ...
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This note was uploaded on 04/08/2011 for the course BIO BM 3350 taught by Professor Blakenship during the Spring '11 term at Cornell University (Engineering School).

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