BIOB 375 1st Edition Lecture 24Outline of Last Lecture II. Genetic Analysisa. PhenotypesOutline of Current Lecture III. Genetic Analysisa. One gene locusi. Pheiotropic effectb. Two gene lociCurrent LectureGenetic analysis – one gene locus (for organisms that are sexually reproduced) One gene locus One characteristic Multiple characteristics (pleiotropic effects of a geneOne allele can associate with multiple phenotypes- Pleiotropic effects of a geneOne gene:- Yellow color -- The suppressor is yellow color- Suppresses Raly expression in the early embryo Embryo abortionOther gene:- Light non-yellow color – The activator is light non-yellow color- Activated Raly overexpression in the early embryoWhen the cell has both activator and suppressor, activator winsThe Lr34 locus in wheat- Has pleiotropic effects- Conferring resistance to rust diseases ( lr34lr34)- Leaf tip necrosis (Lr34Lr34)How do we know that a gene has pleiotropic effects?If in a segregating population for Lr34, 1200 plants were tested to see the response to a fungal pathogenYou should see at least 4 different phenotypesIf you observed two different phenotypes that are always together, its called co-segregating, then it’s possible that the two phenotypes are controlled by the same geneGenetic analysis – two gene loci (for organisms that are sexually reproduced)Two gene loci One characteristic Two
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