The cold tolerance trait of fish has long been studied, due to its importance for
aquaculture. However, most research to date has been focused on physiological factors
such as blood cells, cell membranes, and the enzyme esterase. We report here the first
marker linked to cold tolerance in carp. One of the difficulties for cold tolerance research
in fish is the lack of well-defined lines contrasting with respect to clod tolerance. In this
study, we used a hybrid system with two carps, one of which is cold tolerant and the other
cold sensitive. This hybrid system provided an ideal system for analysis of cold tolerance.
Segregation of the chromosomes and thereby the traits in F2 offered a good system for
further mapping and identification of cold tolerance genes and QTLs. This study is the first
step toward eventual molecular cloning of cold tolerant genes in carps. One marker