Gene Interactions

Genes can and do interact with one another (usually through biochemical pathways). These genes can be on the same chromosome or on different chromosomes. In this post, I will cover three important gene interactions and how they affect the 9:3:3:1.


Recombination Mapping

Recombination mapping is used to determine if two genes are linked (recombination frequency <50%) or unlinked (recombination frequency ~50%). The distance between two genes is measure in either map units (mu) or centiMorgans (cM).

Simple Pedigree Analysis

Pedigrees are diagrams that chronicle the phenotype/genotype of organisms over multiple generations. They can be used to determine the mode of inheritance of a particular disease as well as determine the probability of a future offspring inheriting it.

Do I or Do I Not Express B-Galactosidase?

The lac operon has been covered in another post along with the possible scenarios you could encounter. But what happens to B-galactosidase expression, permease expression and trans-acetylase expression if you have an extrachromosomal F’ factor episome that carries another lac operon? Well, not to fear! I will guide you through a sample problem giving you a systemic method to solve these types of problems.

Do I or Do I Not Complement You?

Complementation testing is done to determine whether two mutants contain a mutation in the same genes or different genes. In research, it is practical to have various mutants that have mutations on the same gene to study its role in the native system. But before one jumps into using these mutants to study a particular gene of interest, one must learn the basics of complementation testing.

The Lac Operon – An Exercise in Systemic Problem Solving

In Escherichia coli, the lac operon allows for the transport and metabolism of lactose. Wild type (WT) E. coli prefers to use glucose as oppose to lactose as its energy source. Therefore, both negative and positive regulation occurs to insure that the lac operon remains tightly regulated and can be induced under appropriate conditions.