Bio 321 F13 lecture 3 v2

Morgan group at columbia in 1908

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Unformatted text preview: unfer0lized eggs) phenomenology of sex linkage in Drosophila melanogaster •  Thomas Hunt Morgan group at Columbia in 1908 –  male with white eyes discovered in a wild type (red eyed) strain •  mated this male to parental strain red eyed females •  all F1 progeny were red eyed •  mated red eyed female F1 to (parent or brother) red eyed male –  female F2: 100% red eyed –  male F2: 50% red eyed, 50% white eyed •  mated F1 male (red eyed) to parental strain red eyed female –  all progeny of both sexes were red eyed •  The muta0on, which Morgan called white, was linked to maleness in this cross; it was sex- linked hZp://en.wikipedia.org/wiki/Thomas_Hunt_Morgan hZp://diogenesii.files.wordpress.com/2010/07/lewis- 16.gif hZp://nobel.caltech.edu/ hZp://991.com/newGallery/Burl- Ives- Song- Book- 294106.jpg hZp://fcdn.filmonic.netdna- cdn.com/wp- content/uploads/2008/03/nedflanders.JPG how did Morgan get white eyed females? •  mate white eyed F1 males to red eyed females whose fathers were white eyed –  males: 50% red eyed, 50% white eyed –  females: 50% red eyed, 50% white eyed hZp://www.schooltr.com/Teacher_Resources/Lesson_Plans/ Lesson_Plan_images/Drowsy_Drosophila27.jpg sex chromosome PunneZ square female gametes X 50% 25% X male gametes 50% XX ♀ 25% Y 50% XY ♂ X 50% 25% XX ♀ 50% females 25% XY ♂ 50% males Drosophila melanogaster white wild type female gametes X+ 50% X+ 50% 25% white- eyed male gametes Xw 50% 25% 25% 25% X+Xw X+Xw ♀ ♀ X+Y X+Y Y ♂ 50% ♂ females: 100% red eyed (all X+Xw heterozygotes) males 100% red eyed (all X+Y hemizygotes) next genera0on (F1 cross) heterozygous female gametes X+ 50% Xw 50% 25% wild type male gametes X+ 50% 25% 25% 25% X+X+ X+Xw ♀ ♀ X+Y XwY Y ♂ 50% ♂ overall Ÿ༉50% of offspring will be red eyed females Ÿ༉25% of offspring will be red eyed males Ÿ༉25% of offspring will be white eyed males females: 100% red eyed Ÿ༉50% are X+X+ homozygotes Ÿ༉50% are X+Xw heterozygotes males 50% red eyed Ÿ༉X+Y hemizygotes 50% white eyed Ÿ༉XwY hemizygotes to generate white eyed females heterozygous female gametes X+ 50% Xw 50% 25% white eyed male gametes Xw 50% 25% 25% 25% X+Xw XwXw ♀ ♀ X+Y XwY Y ♂ 50% ♂ overall Ÿ༉25% of offspring will be red eyed females Ÿ༉25% of offspring wi...
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This note was uploaded on 10/01/2013 for the course BIO 321 taught by Professor John during the Spring '12 term at SUNY Stony Brook.

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