1) Dumpy is a commonly used mutant phenotype in the nematode worm C. elegans Two
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1) Dumpy is a commonly used mutant phenotype in the nematode worm C. elegans Two Dumpy individuals are crossed to each other, and this cross produces 210 Dumpy and 68 wild-type individuals. If one of the Dumpy individuals used in this cross was mated with a wild type, what is the Dumpy: wild- type ratio that we would likely observe in the offspring? a.1:0 c.1:3 d.0:1 e.3:1 2) A mutation occurs in a germ cell of a pure-breeding, wild-type male fruit fly prior to DNA replication The mutation is not corrected, and the germ cell undergoes DNA replication and then a normal meiosis to produce four sperm How many of these four gametes will carry the mutation? a. 0 b. 1 c. 2 d. 3 e. 4 3) A female rabbit of phenotype e' is crossed to a male rabbit with e The Fi is comprised of five rabbits with a e' phenotype, two with eth phenotype, and three with e phenotype. Of the phenotypically e rabbits, two are females and are backcrossed to their father. This cross produces only rabbits with et phenotype. These results suggest that... a. e is dominant to both e' and eth recessive to eh recessive to c b.c is dominant to e', but c. e could be dominant or d. c is dominant to ech but recessive to e e. e is recessive to both e' and eh What is the maximum number of heterozygous genotypes that could be produced by a monohybrid self cross? 4)Explanation / Answer
Q1. answer is 3:1 Dumpy is dominent.
crossing Aa x aa= A and aa with equal probability ,1:1. there can be no AA offspring from this cross.
but there is visible differences between AA and Aa - you can't see there genotypes, you can only see phenotypes: dumpy or wild type. so that 1:0 or 0:1 ratio is meaningless.
the offsprings are simpy dumpy and wildtype , 1:1 .since the dumpy worms have to all be heterozygous so that that is also not the answer.
1:0 and 0:1 would be different from each other such as 3:1 or 1:3.
soo 3:1 is the answer.
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