Question

lizards: completely dominant of st: rough scale (st); smooth scale (s) incompletely dominant sex-linked allele: blue eye (b+); yellow eye (b); green eye (heterozygote) completely dominant and recessive lethal of t*: bent tail (t); straight tail (t") a) What are the parental genotypes for the following phenotypes? i) A smooth, blue eye, straight tail male lizard ii) smooth, green eyed, straight tail female lizard b) After crossing, what will be the appearance and proportion of the offspring? c) For a cross between a normal tail, green eye female and a crooked tail yellow eyed male, both heterozygous at the scale locus. What is the probability of obtaining a rough, yellow eye, crooked tail female in the next generation?

Answer 1

Ans: a. (i) ss b+b+ t+t+

(ii) ss b+b t+t+

b. probsbility is 18.75%

be olyton of a smooth, blue eye, straight tain male lizard, SS 6+6+ ++++ (99 byenotype of a smooth, green eyed, straight tail female lizard, ss 6+ b +++ b. Make prossing bettucen them. O ss b + b + + + 2 + x ss btb tttt s6+++ .......- gametes sbttt sbtt sbtk+ 36+++ Ss 6tht +++ Smooth blue eye, straight tail sbtt | ss b'b tttt smooth, green eye, straight tail 30, there will be two types of off springs, Smooth blu - Smooth seale, blue eye, strough tail lizard. and smooth scale, green eye, storaigh tails lizard and the pacoportion of the offspring is 1:1. Normal tail, green eye, rough scale 1 sts btb tttt cowoked tail, yellow eye, cough seales sts, bb, ett

sts btbtttt 0 stsbb ttt I stbt tt ist btt S+b++ stbt ca Sts +6+b++++lsts+bbt++ rough, green, vrough, yellow, Crooked straight straight ststbtbtttt ststbottt rough, gwer, rough, yellow, corwoved, crooked, w sts btbtttt stsbb tttt lough, geen sough, yellow, straigh I stocmigh sts btbttt sts bbt+t frougly query rough, yellow, Atlaiq bet Isbt ft Isbtt lsts b+b++++ lsts botttt trough; green, vrough, yellow, I staight . stright stsbt ett sts obttt Irwagh, yellow, cowoked Cowoked. SS btbtttt ssbb tttt smooth, gauen, smooth, yellow, straight I straight Iss btbttt Iss bottt smooth green smooth, yellow, sbtt sbt comoved. - Cowolled 1 croreli Covoded . The upowbability of roagh, yellow eye female in the next generation is, 18.75 vwoked tail %