A geneticist is using a three-point testcross to map three linked Drosophila recessive mutations called a, b, and c, where a is associated with anomalous gait, b is associated with buckled wings, and c is associated with curved bristles. She first crosses homozygous anomalous, buckled flies to homozygous curved flies. Next, she testcrosses the F1 progeny to anomalous, buckled, curved flies. She obtains 1000 progeny distributed as shown. From this data, calculate the map distance between b and c. Testcross progeny phenotype Number curved 281 map distance: m. u. anomalous, buckled 279 wild type 4 anamalous, buckled, curved buckled, curved 128 anomalous 132 anomalous, curved 83 buckled 87

a) 1/3 b)1/2 c)1/8

In Drosophila, the allele for long legs (sl*) is wild-type and the allele for short legs (sl) is mutant. The allele for gray body color (b*) is wild-type and the allele for black body color (b') is mutant. The loci for leg length and body color are linked. Flies with sl*sl* b*b* genotypes are mated with flies that have sl s bb genotypes. A testcross was then performed in which the F, offspring with sl*sl b*b genotypes were mated with flies with sl sl. b'b genotypes. The phenotypes of 1000 offspring were recorded. There were 470 flies with long legs and grey body, 30 flies with long legs and black body, 30 flies with short legs and grey body, and 470 flies with short legs and black body. Which of these phenotypes are parental phenotypes? VWhich of these phenotypes are recombinant phenotypes? What is the distance between these two gene loci in centiMorgans (map units)?

There are two genetic disorders that result from mutation in imprinted genes: Prader-Willi syndrome, Angelman syndrome.  Angelman syndrome results from deletion of UBE3A, which is a gene imprinted such that only the maternal copy is expressed. In the pedigree above, individual I-1 is heterozygous for a deletion of UBE3A and does not have Angelman syndrome.  Individual I-2 is homozygous wild type for UBE3A.  Which individuals in the pedigree are at risk for exhibiting Angelman syndrome, if any?  (Who could potentially have the syndrome, based on what alleles it is possible for them to inherit and express?)   Question 8 options:   Only I-1 could have been at risk.  If he does not have the syndrome, no one in the pedigree could.   Only III-1 is at risk   I-1, II-2, and III-1 are all at risk   Only II-2 is at risk   No one in the pedigree is at risk   Both II-2 and III-1 are at…

Females of wild-type Strain A and males of mutant Strain B, as well as females of mutant Strain B and males of wild-type Strain A, make reciprocal crosses. Explain why reciprocal crosses are needed in genetics experiments involving Drosophila fruit flies.

Please explain how you do this question step by step I am very confused! thank you:) You have three independent mutant alleles in the Drosophila gene no-antenna: nan1, nan2 and nan3.  You determine the phenotype of Drosophila that are heterozygous for the three alleles (heterozygous for a wild-type allele and a mutant allele), and that are homozygous for the three mutant alleles.  The antenna is composed of three segments that are followed at the distal end by a feathery arista (that is the antenna is composed of three segments and an arista). Allele nan1 nan2 nan3 heterozygous Wild-type No arista Wild-type homozygous No arista No antenna No antenna nan1 is a __x__ allele, nan2 is a __y__ allele, and nan3 is a __z__ allele.     X Y Z A Dominant negative Null Hypomorphic B Null Dominant negative Hypomorphic C Null Hypomorphic Dominant negative D Hypomorphic Dominant negative Null E Dominant negative Hypomorphic Null Referencing the table above, select the…