Cattle breeding potential mapped In terms of genetic tools, a map of the genome can form a solid basis for further research and breeding. In response to this, European researchers have compiled two bovine radiation hybrid maps using independent methodologies. Health © Shutterstock The overall aim of the European project BOVGEN was to produce a map of the bovine genome which could then be compared or merged with previous bovine maps. A combination of PCR (polymerase chain reaction) primers and expressed sequence tags (ESTs) from an earlier EC funded project and other collaborating laboratories were used to achieve this goal. A radiation mapping technique was used where distances between sequences are proportional to radiation-induced breaks which are in turn related to their actual distances. One advantage of this methodology is that markers do not have to be polymorphic as in the more conventional maps. There are 29 pairs of autosomes and the usual X and Y sex chromosomes in the bovine genome and radiation hybrid (RH) maps were created for the full set. Two independent maps were produced. First, using the ESTs, the total length of the whole genome was calculated together with marker distances and compared with the MARC 2004 linkage map. To create another distinct map using the ESTs, micro-satellite and amplified fragment length polymorphism markers were put through the 'Bead Station' Illumina system producing over 5,000 typed markers. The markers were mapped using two point linkage analysis on already established RH vector sets. The maps produced can be used for further comparing and honing maps produced by other genetic techniques. For the cattle industry, this could mean a better understanding of the genetics behind traits with commercial value.
