Identification, inheritance, and linkage of B-G-like and MHC class I genes in cranes.

We identified B-G-like genes in the whooping and Florida sandhill cranes and linked them to the major histocompatibility complex (MHC). We evaluated the inheritance of B-G-like genes in families of whooping and Florida sandhill cranes using restriction fragment patterns (RFPs). Two B-G-like genes, designated wcbg1 and wcbg2, were located within 8 kb of one another. The fully sequenced wcbg2 gene encodes a B-G IgV-like domain, an additional Ig-like domain, a transmembrane domain, and a single heptad domain typical of alpha-helical coiled coils. Patterns of restriction fragments in DNA from the whooping crane and from a number of other species indicate that the B-G-like gene families of cranes are large with diverse sequences. Segregation of RFPs in families of Florida sandhill cranes provide evidence for genetic polymorphism in the B-G-like genes. The restriction fragments generally segregated in concert with MHC haplotypes assigned by serological typing and by single stranded conformational polymorphism (SSCP) assays based in the second exon of the crane MHC class I genes. This study supports the concept of a long-term association of polymorphic B-G-like genes with the MHC. It also establishes SSCP as a means for evaluating MHC genetic variability in cranes.

A complex alloantigen system in Florida sandhill cranes, Grus canadensis pratensis: evidence for the major histocompatibility (B) system.

The B blood group system constitutes the major histocompatibility complex (Mhc) in birds. The Mhc is a cluster of genes largely devoted to the processing and presentation of antigen. The Mhc is highly polymorphic in many species and, thus, useful in the evaluation of genetic diversity for fitness traits within populations of a variety of animals. Correlations found between particular Mhc haplotypes and resistance to certain diseases emphasize the importance of understanding the functional significance of diversity of the Mhc, particularly in species threatened with extinction. As part of studies focused on genetic diversity in wild birds, serological techniques were used to define a highly polymorphic alloantigen system in seven families of Florida sandhill cranes (Grus canadensis pratensis). The results of analyses with antisera produced within the crane families and with chicken Mhc antigen-specific reagents revealed a single major alloantigen system that is likely the Mhc of the Florida sandhill crane. Preliminary experiments indicate that these crane alloantisera will provide a means of defining the Mhc in other species of cranes.

Environmental contaminants in nonviable eggs of the endangered Mississippi sandhill crane (Grus canadensis pulla).

Our objectives were to determine if concentrations of environmental pollutants and microbial contamination in nonviable eggs of the endangered Mississippi sandhill crane (Grus canadensis pulla) contributed to egg failure. Six eggs collected in 1990 and four in 1991 contained only background levels of organochlorine pesticides and polychlorinated biphenyls (PCBs), and tests for microbial contamination were all negative. Two eggs contained late dead embryos, but neither revealed obvious abnormalities. Three eggs contained potentially harmful concentrations (23, 39, 146 pg/g, wet mass) of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), based on 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQ) for combined compounds. Because of the scarcity of material suitable for laboratory examination and the endangered status of the crane, we recommend that nonviable eggs continue to be monitored for toxic pollutants.

Allozyme evidence for crane systematics and polymorphisms within populations of Sandhill, Sarus, Siberian, and whooping cranes.

Electrophoretic analysis of proteins yielded evidence on the relationships of species of cranes and on genetic diversity within populations of some species. Diversity within the Greater Sandhill crane and a Florida population of the Florida Sandhill crane was similar to that of most other vertebrates, but diversity was low in the Mississippi Sandhill crane, in the Okefenokee population of the Florida Sandhill crane, and within the Siberian and Sarus cranes. Diversity was surprisingly high among whooping cranes, whose number dropped to less than 25 early in this century. Phylogenetic analysis, using both character state and distance algorithms, yielded highly concordant trees for the 15 species. The African crowned cranes (Balearica) were widely divergent from all other cranes. Species of Anthropoides, Bugeranus, and Grus clustered closely but sorted into two lineages: a Whooper Group consisted of the whooping, common, hooded, black-necked, white-naped, and red-crowned cranes of genus Grus; and a Sandhill Group included the Sandhill, Siberian, Sarus, and Brolga cranes of genus Grus, the wattled crane of genus Bugeranus, and the Demoiselle and blue cranes of genus Anthropoides.

Sperm head length as a predictor of fecundity in the sandhill crane, Grus canadensis.

Semen samples from 14 sandhill cranes were collected for 15 weeks. Mean sperm head length which did not vary significantly over weeks was found to be significantly correlated with fertility (P less than 0 . 04; r = 0 . 54, n = 14).