MCDB 1A - generation. 8.The genotypes are: PpSwsw Ppswsw...

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Answers to Genetics Problems (pg 230-231) 1. Each of the eight boxes in the Punnett squares should contain the genotype Tt , regardless of which parent was tall and which dwarf. 2. See Figure 10.4, page 212. 3. The trait is autosomal. Mother dp dp , father Dp dp . If the trait were sexlinked, all daughters would be wild-type and sons would be dumpy . 4.Yellow parent = s Y s b ; offspring 3 yellow ( s Y –): 1 black ( s b s b ). Black parent = s b s b ; offspring all black ( s b s b ). Orange parent = s O s b ; offspring 3 orange ( s O –): 1 black ( s b s b ). Both s O and s Y are dominant to s b . 5. All females wild-type; all males spotted. 6. F1 all wild-type, PpSwsw ; F2 9:3:3:1 in phenotypes. See Figure 10.7, page 214, for analogous genotypes. 7 a . Ratio of phenotypes in F2 is 3:1 (double dominant to double recessive). 7 b .The F1 are Pby pBY ; they produce just two kinds of gametes ( Pby and pBy ). Combine them carefully and see the 1:2:1 phenotypic ratio fall out in the F2. 7 c . Pink-blistery. 7 d . See Figures 9.16 and 9.18 (pages 196–198). Crossing over took place in the F1
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Unformatted text preview: generation. 8.The genotypes are: PpSwsw Ppswsw ppSwsw ppswsw Ratio: 1:1:1:1 The phenotypes are: wild eye, long wing pink eye, long wing wild eye, short wing pink eye, short wing Ratio: 1:1:1:1 9 a . 1 black:2 blue:1 splashed white 9 b .Always cross black with splashed white. 10 a . w + > w e > w 10 b . Parents w e w and w + Y . Progeny w + w e , w + w , w e Y , and w Y . 11. All will have normal vision because they inherit dads wild-type X chromosome, but half of them will be carriers. 12. Agouti parent AaBb . Albino offspring aaBb and aabb ; black offspring Aabb ; agouti offspring AaBb . 13. Because the gene is carried on mitochondrial DNA, it is passed through the mother only. Thus if the woman does not have the disease but her husband does, their child will not be affected. On the other hand, if the woman has the disease but her husband does not, their child will have the disease....
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This note was uploaded on 10/08/2010 for the course MCDB MCDB 1A taught by Professor Senghuilow during the Summer '09 term at UCSB.

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