Trop Team
Search Harland trop site
Obtain Embryos
Genomic Resources
Trop Labs

Inbred Strains

Inbred strains are important for genetic screens to simplify phenotypes that might otherwise be complicated due to polymorphic effects.

Currently very few X. tropicalis inbred strains are available. However due to the efforts of several labs, strains derived from frogs from Nigeria and Ivory Coast have been inbred through multiple generations. A Nigerian strain has been used to produce genomic DNA for BAC libraries and BAC mapping (CHORI and Wash U.) as well as genomic sequencing (JGI). The Ivory Coast and Nigerian strains are being used to create a genetic linkage map.

We have created trees illustrating the genealogy of the various strains being propogated in our lab and their relation to frogs being inbred in other labs. These trees should provide a common language to understand the relations of particular frogs to various holotypes.

Nigerian tree (PDF)

Ivory Coast (via Virginia) tree (PDF)

Population A (PDF)

Goldens (PDF)

Ivory Coast (PDF) via France [Nicolas Pollet]

Because of the nature of some of our inbreeding (especially the backcross), determining the inbreeding generation was becoming difficult. Therefore we adopted the convention that an animal generated by a backcross was one half more inbred than the most inbred parent that generated it. For example, if a F5 inbred animal is backcrossed to its mother (F4) then the resultant progeny are F5.5. This designation allows us to identify those animals which have been inbred by backcrossing and their relative degree of inbreeding. We can then use the formula [(X+Y)/2]+1 to determine an F number for any pair of animals (where X, Y are the F numbers of the parents).

We have used this formula throughout our trees. Caution should be taken however. While the formula can give precise F numbers, it is only an approximation and works effectively only if the F numbers are relatively similar since the degree of inbreeding is non-linear. However, it has been very helpful in making our trees so we have fully adopted it. In order to use the calculator below, enter the parental F numbers in X and Y and then hit calculate!

Special thanks to Kurt Stephenson for collecting the data and creating the initial trees (Ivory Coast and Nigerian). Dan Roche and Mustafa Khokha adapted these trees into html and PDF pages. Timothy Grammer updated the trees and created ones for population A, Golden, and the French Ivory Coast and independently developed the F number formula and has a Grand Unifying Theory of Everything which he will gladly expound upon for hours at a time. Thanks to Patrick Cheatham for creating the calculator and Maura Lane for making fun of Tim.