Tetrad protocol - TETRAD ANALYSIS - HAPLOID MAPPING All...

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TETRAD ANALYSIS - HAPLOID MAPPING All fungi produce spores, however, some (the  ascomycetes ) are conspicuous,  because the spores are encased in a sac-like structures ( asci ) which can be recovered  intact. This makes it possible to study the products of individual meiotic divisions,  making the  ascomycetes  ideal for studying recombination.  Like the fruit fly,  ascomycetes  produce lots of progeny and are easy to grow, but one  characteristic makes them especially useful for studying recessive mutations; they are  haploid. As such dominance is not an issue since the genotype is expressed directly in  the phenotype. LINEAR TETRADS In  Neurospora crassa  and  Sordaria fimicola , two species extensively used for  genetic investigations, the  asci  are long cylindrical tubes in which the spores are  produced end to end, resulting in ordered arrays of spores (See the figure below.)  A  zygote nucleus (the  diploid  product of the union of cells of opposite mating types,)  which is contained in an  ascus undergoes  meiotic division  almost immediately after it  is formed.  The four  haploid  nuclei produced by meiosis are in a linear order in the 
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This note was uploaded on 05/03/2008 for the course BIO 2322 taught by Professor Spotswood during the Spring '08 term at Texas San Antonio.

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Tetrad protocol - TETRAD ANALYSIS - HAPLOID MAPPING All...

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