Low major histocompatibility complex class II diversity in European and North American moose.

Major histocompatibility complex (MHC) genes encode cell surface proteins whose function is to bind and present intracellularly processed peptides to T lymphocytes of the immune system. Extensive MHC diversity has been documented in many species and is maintained by some form of balancing selection. We report here that both European and North American populations of moose (Alces alces) exhibit very low levels of genetic diversity at an expressed MHC class II DRB locus. The observed polymorphism was restricted to six amino acid substitutions, all in the peptide binding site, and four of these were shared between continents. The data imply that the moose have lost MHC diversity in a population bottleneck, prior to the divergence of the Old and New World subspecies. Sequence analysis of mtDNA showed that the two subspecies diverged at least 100,000 years ago. Thus, viable moose populations with very restricted MHC diversity have been maintained for a long period of time. Both positive selection for polymorphism and intraexonic recombination have contributed to the generation of MHC diversity after the putative bottleneck.

European and North American Railway, New England and Eastern Canada, 1850 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Map of the European and North American Railway : showing its connection with the railways of the United States & Canada, [by] A.C. Morton, engineer. It was published in 1850 by Bowen & Co. Scale [ca. 1:1,625,000]. Covers New England, eastern New York, and the Maritime Provinces. The image inside the map neatline is georeferenced to the surface of the earth and fit to the USA Contiguous Albers Equal Area Conic projection (Meters). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, or other information associated with the principal map. This map shows features such as completed, in progress, and proposed railroads, selected towns, drainage, state boundaries, and more. Includes inset: Map showing the plan for shortening the transit between New York & London. This layer is part of a selection of digitally scanned and georeferenced historic maps of New England from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

The Round goby, Neogobius melanostomus (Pallas) : a review of European and North American literature /

"Sea Grant Publication No. IL-IN-SG-97-7"--P. 2 of cover.