A high resolution RH map of the bovine major histocompatibility complex.

BACKGROUND: The cattle MHC is termed the bovine leukocyte antigen (BoLA) and, along with the MHCs of other ruminants, is unique in its genomic organization. Consequently, correct and reliable gene maps and sequence information are critical to the study of the BoLA region. The bovine genome sequencing project has produced two assemblies (Btau_3.1 and 4.0) that differ substantially from each other and from conventional gene maps in the BoLA region. To independently compare the accuracies of the different sequence assemblies, we have generated a high resolution map of BoLA using a 12,000rad radiation hybrid panel. Seventy-seven unique sequence tagged site (STS) markers chosen at approximately 50 kb intervals from the Btau 2.0 assembly and spanning the IIa-III-I and IIb regions of the bovine MHC were mapped on a 12,000rad bovine radiation hybrid (RH) panel to evaluate the different assemblies of the bovine genome sequence. RESULTS: Analysis of the data generated a high resolution RH map of BoLA that was significantly different from the Btau_3.1 assembly of the bovine genome but in good agreement with the Btau_4.0 assembly. Of the few discordancies between the RH map and Btau_4.0, most could be attributed to closely spaced markers that could not be precisely ordered in the RH panel. One probable incorrectly-assembled sequence and three missing sequences were noted in the Btau_4.0 assembly. The RH map of BoLA is also highly concordant with the sequence-based map of HLA (NCBI build 36) when reordered to account for the ancestral inversion in the ruminant MHC. CONCLUSION: These results strongly suggest that studies using Btau_3.1 for analyses of the BoLA region should be reevaluated in light of the Btau_4.0 assembly and indicate that additional research is needed to produce a complete assembly of the BoLA genomic sequences.

The influence of temperature on the functional response of the dragonfly Celithemis fasciata (Odonata: Libellulidae).

1) Functional response curves were constructed for Celithemis fasciata larvae feeding on 6 different densities of midge larvae at 10, 15, 20, and 25°C. Values for attack rate and handling time were estimated with Rogers's random predator equation. 2) Polynomial regression revealed that the functional response curves were linear although a tendency toward decreasing consumption rates at higher densities was shown. 3) The mean number of prey eaten increased with temperature; however, temperature did not alter the fundamental shape of the functional response curve. 4) The attack rate and handling time were linearly related to temperature in general, but changed relatively little between 15 and 20° C.