Re-evaluation of LG V of the rat and assignment of 12 carboxylesterases to two gene clusters.

Examining the strain distribution pattern of the recombinant inbred strain series LXB and DXE and of backcross progeny of (LEW X LE)F1 X LEW, (LEW X BN)F1 X LEW, and (LEW X BN)F1 X BN for esterase markers, including three carboxylesterase allozymes (ES-15, ES-16, ES-18), hitherto not studied genetically, revealed the existence of two esterase gene clusters within LG V: cluster 1, containing Es-2, Es-8, Es-10, Es-3, Es-7, Es-9, and separated by 8.8 +/- 1.3 cM from cluster 2, containing Es-1, Es-14 (formerly Es-Si), Es-15, Es-16, and Es-18. Analyses of 93 inbred strains of rats showed only 12 and 6 haplotypes for cluster 1 and cluster 2, respectively, indicating a strong linkage disequilibrium. These data and serotyping results of one backcross population for the RT2 blood group system lead to a re-evaluation of linkage group V. Including literature data the following gene order is suggested: RT2 - (7.1 +/- 1.8) Es-2, Es-4, Es-8, Es-10 (2.7 +/- 0.7) Es-3, Es-7, Es-9 (8.8 +/- 1.3) Es-1, Es-14, Es-15, Es-16, Es-18.