To locate genes associated with quantitative traits, geneticists often use QTL mapping (see the introduction to this chapter). To carry out QTL mapping, a first step is crossing two strains that differ in a quantitative trait, such as a strain of corn with high oil content and a strain with low oil content. The F1 progeny of this cross are then interbred or backcrossed to produce an F2 generation. Researchers then look for statistical associations between genetic markers and the value of the quantitative trait (e.g., oil content) in the F2 generation. Why do the geneticists look for statistical associations in the F2 plants? Why not use the F1 progeny?

You would like to isolate loci in the genome that influence plant height in tomato plants. Describe how you would achieve this through QTL mapping. Choose a true breeding tall strain and a true breeding short strain and compare the genomic sequences. Choose a true breeding tall strain and true breeding short strain and type them for molecular markers. Mate them together to produce F1 offspring and evaluate whether the F1 are tall or short. Choose two true breeding tall strains and compare the genomic sequences. Choose a true breeding tall strain and true breeding short strain and type them for molecular markers. Mate them together to produce F1 offspring. Genotype the F1 to identify makers that are associated with differences in plant height. Choose a true breeding tall strain and true breeding short strain and type them for molecular markers. Mate them together to produce F1 offspring, then backeross the F1 offspring to produce F2 offspring carrying recombinant chromosomes from tall…

According to Amar J. S. Klar, is there a such thing as “left handedness”? What is the preferred term? Describe how the genetics works, according to his hypothesis. What are the alleles, and which combinations of alleles make for which type of hand use?

A) For the 3-point test cross, draw a sample gene map. B) Give the map distances (include units). C) Calculate Interference (I) and COC. Show all work Fly trait body texture, antenna shape, eye color gaunt, normal, white gaunt, feathery, white gaunt, feathery, red shrunken, feathery, white shrunken, normal, white shrunken, feathery, red gaunt, normal, red shrunken, normal, red Total number of progeny: Gamete from trihybrid GNr Gnr GnR gnr gNr gnR GNR gNR Number 628 2708 113 3 124 661 2 2761 7000