Question

Genetics Worksheet BIO-1 Answer the following questions on a separate piece of paper. You MUST SHOW YOUR WORK In Jurassic Park, blood from dinosaurs was found in mosquitoes trapped in amber. DNA from the blood was used to clone live beasts. If this had been true, we would also have been able to eventually learn much about Jurassic genetics. Let's pretend that 1. It was found that in T. rex a single gene controlled claw shape, and that curled claws were dominant to straight claws (Let C = curled allele and c = straight allele). a. Give all the possible genotypes and their associated phenotypes. b. Say you were to cross a pure-breeding curled clawed T. rex with a pure-breeding straight clawed beast. Show the genotypes and phenotypes of the P and F, animals. c. You then crossed two of the F, animals with each other. What genotypic and phenotypic proportions would you expect in the F2?

Answer 1

A. If C= curled allele and c= straight allele, then the possible genotypes will be as follows:

CC- double dominant

Cc- heterozygous dominant and

cc- double recessive

The possible phenotypes will be curled claws (CC and Cc) and straight claws (cc).

B. If we cross a pure breeding curled clawed T.rex with a pure breeding straight clawed T.rex,

The phenotypes and genotypes of the P will be curled (CC) and straight (cc) claws.

The genotypes of F1 animals are as follows:

C/c	c	c
C	Cc	Cc
C	Cc	Cc

The phenotypes are all curled clawed animals (Cc).

The genotypes are Cc, Cc, Cc, and Cc.

C. If we crossed two F 1 animals with each other, the genotypes would be as

Cc/Cc	C	c
C	CC	Cc
c	Cc	cc

The phenotypic proportions of F2 generation would be 3:1(curled claws: straight claws).

The genotypic proportions of F 2generation would be 1:2:1(curled homozygous: curled heterozygous: straight homozygous).