ASSIGNMENT OF GENES TO CHROMOSOME 4 OF THE RIVER BUFFALO WITH A PANELOF BUFFALO-HAMSTER HYBRID-CELLS

To identify the river buffalo chromosome carrying the genes coding for GAPD, TPI1, and LDHB, karyotypic examination was carried out on 14 bu ffalo-hamster hybrid clones previously tested for presence of this syn tenic group. In cattle, this group (U3) has been assigned to chromosom e 5, which is assumed to be homologous to the long arm of buffalo chro mosome 4. Chromosome 4 was present in all five clones expressing the t hree enzymes, and absent in all seven negative clones, indicating that in the buffalo GAPD, TPI1, and LDHB are located on chromosome 4. One clone, expressing GAPD and TPI1, but not LDHB, was found to carry a tr anslocation between hamster marker chromosome M2 and buffalo 4q1 --> 4 qter. In another clone, expressing LDHB, but not GAPD and TPI1, chromo some 4 was absent, while a very small, unidentifiable acrocentric was present. These observations suggest that LDHB is located in the proxim al part of 4q1, and that GAPD and TPI1 are located more distally, in 4 q1 --> 4q2.