Transposible Genetic Elements

Suppose a chromosome carries two copies of a transposing in the same orientation. The order of the genes on the chromosome is ABCDEFGHI, and one transposon is located between genes F and G. If the two transposons pair and then a crossover occurs, what will the order of the genes be in the resulting chromosome?

ABCGHI

What is transposase?

An enzyme required for transposons to move. AKA as “jumping genes” within a cell’s genome

IS transposons create target site duplications when they move around. How?

When IS elements cut the DNA to insert, they create a duplication on either side as part of the DNA at the site of insertion, when they leave they leave the duplications behind

What is a composite transposon?

A composite transposon is a bacterial cut and paste transposon that captures a piece of the bacterial genome and can move it, these are characterized by an IS element at each end

A conjugative plasmid is one that:

Can carry a transposon from one bacterial cell to another

In maize, Ds requires the second transposon AC to move. Why?

Ac codes for transposase, which Ds does not contain

What is the genotype of the endosperm from a wild-type kernel that is fertilized by pollen from a colorless mutant, C’?

CCC’

What is a long terminal repeat?

A signature at the end of a retrovirus, produced when the RNA is reverse transcribed into DNA