Niche Lesson 4-S

Who discovered that two traits did not assort independently in 1905?

William Bateson and Reginald Punnett.

What did Bateson and Punnett discover in 1905?

They discovered that two traits could be inherited together instead of assorting independently.

What does linkage refer to in genetics?

The tendency of genes located close together on the same chromosome to be inherited together.

How is data grouped for linkage analysis?

Data is always grouped into two phenotypic classes.

What is Drosophila melanogaster?

The scientific name for the common fruit fly.

Who invented a method to quantify the relationship between recombination rate and gene distance?

Alfred Sturtevant, an undergraduate student of Thomas Hunt Morgan.

At what age did Sturtevant develop his recombination mapping method?

At 21 years old.

What did Sturtevant’s method quantify?

The relationship between the rate of recombination and the distance between genes.

What is a two-point cross?

A genetic cross comparing two genes to determine their relative positions on a chromosome.

What do two-point crosses help establish?

The relative positions of genes on a chromosome.

What are the limitations of two-point crosses?

1. Difficult to determine gene order if genes are close together. 2. Actual distances between genes do not always add up. 3. Pairwise crosses are time-consuming and labor-intensive.