After studying an iguana species on a Pacific island, you conclude that there ar
ID: 188916 • Letter: A
Question
After studying an iguana species on a Pacific island, you conclude that there are two true-breeding strains: strain A is green and has a spikey tail and strain B is blue and has a smooth tail. A cross between a female of strain A and a male of strain B produces all green, smooth-tailed offspring. A cross between the F1's results in the following progeny at the frequencies indicated.
Green, smooth-tailed females 3/8
Green, smooth-tailed males 3/16
Blue, smooth-tailed males 3/16
Green, spikey-tailed females 1/8
Green, spikey-tailed males 1/16
Blue, spikey-tailed males 1/16
a. What are the genotype of the original strains and F1 progeny?
b. What are the genotype of the F2 progeny? Indicate in the blanks above.
c. What phenotypes will offspring have from a cross of blue, spikey-tailed F2 males with original strain B females?
Explanation / Answer
ANSWER: a) strain A - CCss genotype
strain B- ccSS genotype
where Cc- represent color ( both dominant & reccessive) and,
Ss- represent tail characteristics
F1 progeny- CcSs
b) genotypes of F2 progeny - CCSS, CCSs, CCss, CcSS, CcSs, Ccss, ccSS, ccSs, ccss
in the ratio of 1:2:1:2:4:2:1:2:1 respectively
c) green, spikey- tailed offsprings