MIT Biology Department 7.012: Introductory Biology-Fall 2004 Instructors: Professor Eric Lander, Professor Robert A Weinberg, Dr. Claudette Gardel Solutions to 7.012 Problem set 3 Question 1 You have two pure-breeding colony of mice. Colony I mice have black fur and long tails, Colony II mice have golden fur and short tails You cross mice from each of these colonies black fur and colden fur and long hort tails Brown fur and long tails a)Predict genotypes for the mice shown in the cross above. Define your notation. i) black fur and long tails: BB LL ii) golden fur and short tails: B'B'll iii)Brown fur and long tails: BB'LI b)You mate a male and a female from the F, generation. Given your prediction in(a), what genotypes and phenotypes do you see in the F2 generation, and in what ratios? BB′ LIX BE'Ll BL B′L BL BBLL BBLI BBLL BBLI black fur and long black fur and lons long tailand brown fur long tails BI BBLI BBlL BBLl BB'll black fur and long black fur and short brown fur and brown fur and long tails short tails BL BBLL BBLL BBLL an d grown fur a en fur ah id golden fur and long tails long tails long tails long tails B'I BBLl BB'll B'B'LL B'B'll brown fur and brown fur and olden fur and golden fur and long tails short tails long tails chort tails 012Fal20037.012 Fall 2003 Solutions to 7.012 Problem Set 3 Question 1 You have two pure-breeding colony of mice. Colony I mice have black fur and long tails, Colony II mice have golden fur and short tails. You cross mice from each of these colonies. F0 black fur and long tails X golden fur and short tails
F1 Brown fur and long tails a) Predict genotypes for the mice shown in the cross above. Define your notation. i) black fur and long tails: BB LL ii) golden fur and short tails: B’B’ ll iii) Brown fur and long tails: BB’ Ll b) You mate a male and a female from the F1 generation. Given your prediction in (a), what genotypes and phenotypes do you see in the F2 generation, and in what ratios? BB’ Ll X BB’ Ll BL Bl B’L B’l BL BBLL black fur and long tails BBLl black fur and long tails BB’LL brown fur and long tails BB’Ll brown fur and long tails Bl BBLl black fur and long tails BBll black fur and short tails BB’Ll brown fur and long tails BB’ll brown fur and short tails B’L BB’LL brown fur and long tails BB’Ll brown fur and long tails B’B’LL golden fur and long tails B’B’Ll golden fur and long tails B’l BB’Ll brown fur and long tails BB’ll brown fur and short tails B’B’Ll golden fur and long tails B’B’ll golden fur and short tails MIT Biology Department 7.012: Introductory Biology - Fall 2004 Instructors: Professor Eric Lander, Professor Robert A. Weinberg, Dr. Claudette Gardel