BIOL 430 2010 lecture 7 handout 6 slides

BIOL 430 2010 lecture 7 handout 6 slides - How do we...

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1 BIOL 430 Lecture 7 January 26 th 2010 How do we identify genes involved in development? Making transgenic animals BIOL 430 2010 Molecular Genetics of Development Dr. Ian Chin-Sang www.chin-sang.ca Mosaic analysis How do we Isolate Genes involved in Development? Mutagens Type of Mutagen Type of DNA Damage Applications Chemical mutagenesis(i.e. EMS or ENU N ethylinitrosourea (ENU) Base Pair Change point mutation GC to AT Saturation mutagenesis, efficient (1/1000), random, isolate any type of mutation lof or go BIOL 430 2010 Molecular Genetics of Development Dr. Ian Chin-Sang www.chin-sang.ca N-ethylinitrosourea (ENU) ehtylmethanesulfonate (EMS) of mutation lof or gof Transposons (i.e. P element or Tc1) DNA insertion not quite random, provides a “tag” for cloning, isolate loss of function mutations as well as gain of function mutations Irradiation (X rays γ rays) Deletions and chromosomal rearrangements inefficient (1/10 000) random, usually isolate null mutations Male fish are mutagenized (ENU) Identification of recessive Mutations n zebra fish 1000’s of individual crosses required m/+ +/+ or or rare event leads to mutation m/+ BIOL 430 2010 Molecular Genetics of Development Dr. Ian Chin-Sang www.chin-sang.ca 25% of progeny mutant can maintain as homozygote or as a het if the mutation is lethal Raise families 50% are +/+ 50% are =+/m Only the double het cross wil give rise to 25% mutant progeny m/+ +/+ m/+ +/+ m/+ m/+ m/+ m/+ +/+ +/+ +/+ +/+ BOX 3B p. 99 gene “c” is recessive lethal mutation a b c d e f X 5’ 3’ a b c d e f X Dead (homozygous m/m) BIOL 430 2010 Molecular Genetics of Development Dr. Ian Chin-Sang www.chin-sang.ca gene “c” is recessive lethal mutation a b c d e f X 5’ 3’ a b c d e f Alive (heterozygous +/m) gene “c” is recessive lethal mutation a b c d e f 5’ 3’ a b c d e f Alive (heterozygous) a b c d e f 5’ 3’ a b c d e f Alive (heterozygous) cross BIOL 430 2010 Molecular Genetics of Development Dr. Ian Chin-Sang www.chin-sang.ca a b c d e f a b c d e f a b c d e f a b c d e f a b c d e f a b c d e f 25% alive +/+ 50% alive +/m 25% dead m/m Phenotypically theses look the same. Concept of a Balancer Chromosome
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This note was uploaded on 12/06/2011 for the course BIOL 430 taught by Professor Dr.ianchin-sang during the Winter '10 term at Queens University.

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BIOL 430 2010 lecture 7 handout 6 slides - How do we...

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