Pax-6 usually causes the production of a type of light-receptor pigments. In vertebrate eyes, though, a different gene (the rh gene family) is responsible for the light-receptor pigments of the retina. The rh gene, like Pax-6, is ancient. In the marine ragworm, for example, the rh gene causes production of c-opsin, which helps regulate the wormʹs biological clock. Which of these most likely accounts for vertebrate vision?

TLS Online TPP Program

#Question id: 15835

#Unit 8. Inheritance Biology

You are interested in a new type of autosomal dominant mutation that gives purple eyes in Drosophila. You have a true-breeding purple-eyed line carrying a mutation that you call pr-1. You have isolated a second purple-eyed mutation that you call pr-2, which you have established in a true-breeding line that also carries a recessive marker st, which gives stubby legs. You cross a fly from the pr-1 line to a fly from the st, pr-2 line producing F1 females which you then cross to males from a true breeding st line (normal eyes). From this cross, 1000 progeny flies can be categorized into four different phenotypic classes:

                       

What is the distance between pr-1 and pr-2 in cM?

TLS Online TPP Program

#Question id: 15836

#Unit 8. Inheritance Biology

You are interested in a new type of autosomal dominant mutation that gives purple eyes in Drosophila. You have a true-breeding purple-eyed line carrying a mutation that you call pr-1. You have isolated a second purple-eyed mutation that you call pr-2, which you have established in a true-breeding line that also carries a recessive marker st, which gives stubby legs. You cross a fly from the pr-1 line to a fly from the st, pr-2 line producing F1 females which you then cross to males from a true breeding st line (normal eyes). From this cross, 1000 progeny flies can be categorized into four different phenotypic classes:

                   

What is the phenotype of a pr-1 pr-2 double mutant?

TLS Online TPP Program

#Question id: 15837

#Unit 8. Inheritance Biology

You are interested in a new type of autosomal dominant mutation that gives purple eyes in Drosophila. You have a true-breeding purple-eyed line carrying a mutation that you call pr-1. You have isolated a second purple-eyed mutation that you call pr-2, which you have established in a true-breeding line that also carries a recessive marker st, which gives stubby legs. You cross a fly from the pr-1 line to a fly from the st, pr-2 line producing F1 females which you then cross to males from a true breeding st line (normal eyes). From this cross, 1000 progeny flies can be categorized into four different phenotypic classes:

                      

What is the relative order of st, pr-1 and pr-2?

TLS Online TPP Program

#Question id: 15838

#Unit 8. Inheritance Biology

You are interested in a new type of autosomal dominant mutation that gives purple eyes in Drosophila. You have a true-breeding purple-eyed line carrying a mutation that you call pr-1. You have isolated a second purple-eyed mutation that you call pr-2, which you have established in a true-breeding line that also carries a recessive marker st, which gives stubby legs. You cross a fly from the pr-1 line to a fly from the st, pr-2 line producing F1 females which you then cross to males from a true breeding st line (normal eyes). From this cross, 1000 progeny flies can be categorized into four different phenotypic classes:

 

What is the distance between the st and pr genes?

TLS Online TPP Program

#Question id: 15839

#Unit 8. Inheritance Biology

In the yeast cross of ade2 met14 his3 x + + +, a total of 120 tetrads are analyzed. The following tetrad types are found in the numbers shown below each tetrad. The markers ade2, met14, and his3 are abbreviated a, m, and h and the wild type allele of each gene is indicated by +.

 

Use this categorization and the numbers of each type to determine which (if any) of the three markers are linked. For any linked markers, calculate the distance between them in cM.      

To measure the distance between two linked His– mutations, you cross a his2– mutant to a his4– mutant and then dissect 100 tetrads. Your lab partner records which spore clones are His+ and which are His– ; but then the fool loses the papers on which most of the data is recorded. In the end all he can remember is that there were three different tetrad types an that there was only one tetrad of the type with 2 His+ and 2 His– spore clones.

TLS Online TPP Program

#Question id: 15840

#Unit 8. Inheritance Biology

In the yeast cross of ade2 met14 his3 x + + +, a total of 120 tetrads are analyzed. The following tetrad types are found in the numbers shown below each tetrad. The markers ade2, met14, and his3 are abbreviated a, m, and h and the wild type allele of each gene is indicated by +.

 

What were the other two types of tetrads (how many His+ and His– spores do they have)?