Search

The feather beta ([beta]) keratins of the white leghorn chicken (order Galliformes, Gallus gallus domesticus) are the products of a multigene family that includes claw, feather, feather-like, and scale genes (Presland et al. 1989a). Here we characterize the feather [beta]-keratin genes in additional bird species. We designed primers for polymerase chain reactions (PCR) using sequences available from chicken, cloned the resulting amplicons to isolate individual copies, and sequenced multiple clones from each PCR reaction for which we obtained amplicons of the expected size. Feather [beta]-keratins of 18 species from eight avian orders demonstrate DNA sequence variation within and among taxa, even in the protein-coding regions of the genes. Phylogenies of these data suggest that Galliformes (fowl-like birds), Psittaciformes (parrots), and possibly Falconiformes (birds of prey) existed as separate lineages before duplication of the feather [beta]-keratin gene began in Ciconiiformes (herons, storks, and allies), Gruiformes (cranes, rails, and allies), and Piciformes (woodpeckers and allies). Sequences from single species of Coraciiformes (kingfishers) and Columbiformes (pigeons) are monophyletic and strikingly divergent, suggesting feather [beta]-keratin genes in these birds also diverged after these species last shared a common ancestor with the other taxa investigated. Overall, these data demonstrate considerable variation in this structural protein in the relatively recent history of birds, and raise questions concerning the origin and homology of claw, feather-like, and scale [beta]-keratins of birds and the reptilian [beta]-keratins.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2006.08.010 Byline: H. Bobby Fokidis, Thomas S. Risch, Travis C. Glenn Abstract: Factors underlying the evolution of female-biased sexual size dimorphism in mammals are poorly understood. In an effort to better understand these factors we tested whether larger female southern flying squirrels, Glaucomys volans, gained reproductive advantages (larger litters or more male mates) and direct resource benefits, such as larger home ranges or access to more food (i.e. mast-producing trees). As dimorphism can vary with age in precocial breeding species, we compared females during their first reproduction and during a subsequent breeding attempt. Females were not significantly larger or heavier than males at first reproduction, but became about 7% heavier and 22% larger than males at subsequent breeding. Larger females produced larger litters and had home ranges containing a greater proportion of upland hardwood trees. Female body size was not associated with either multiple male mating or home range size, but females with larger home ranges had higher indexes of body condition. Females in precocial breeding flying squirrels initiate reproduction before sexual size dimorphism is evident, and thus, may be allocating resources to both reproduction and growth simultaneously, or delaying growth entirely. Larger females produce more pups and have access to more food resources. Thus, selection for increased female size may partly explain how female-biased sexual size dimorphism is maintained in this species. Author Affiliation: (a) Department of Biological Sciences, Arkansas State University, U.S.A. (a ) Savannah River Ecology Laboratory, U.S.A. Article History: Received 11 April 2006; Revised 9 June 2006; Accepted 12 August 2006 Article Note: (miscellaneous) MS. number: A10419R

Genetic and clonal diversity vary between two closely related cattail species (Typha angustifolia and T. latifolia) from Ukraine. This diversity was calculated from microsatellite data. Forty-eight percent of the total variation was partitioned between species, which formed distinct clusters in a dendrogram with no indication of hybrid populations. Typha angustifolia had higher heterozygosity at the species ([H.sub.es] = 0.66) and population ([H.sub.ep] = 0.49) levels than did T. latifolia ([H.sub.es] = 0.37 and [H.sub.ep] = 0.29, respectively). The higher number of alleles in T. angustifolia may be indicative of larger effective population sizes due to its higher seed production. Clonal diversity of T. angustifolia was lower than that of T. latifolia ([N.sub.g]/[N.sub.r] = 0.40 and 0.61, Simpson's D = 0.82 and 0.94, respectively). Correlations between clonal and genetic diversity were higher for T. latifolia than T. angustifolia, suggesting that the importance of factors and their interactions affecting this relationship are different for the two species. Latitudinal and longitudinal trends were not observed in either species despite the large sampling area. Population differentiation was relatively high with [F.sub.ST] of 0.24 and 0.29 for T. angustifolia and T. latifolia, respectively. Weak isolation by distance was observed for T. latifolia but not for T. angustifolia. Key words: cattails; clonal structure; genetic diversity; microsatellites; Typha angustifolia; Typha latifolia; Ukraine.

We assessed the effects of range disjunction, migratory habit, coloniality, and habitat structure on the genetic differentiation of North American Burrowing Owl (Athene cunicularia) populations. Burrowing Owls in North America comprise two forms or subspecies: A. c. floridana in Florida, separated by ~1,500 km from the western form, A. c. hypugaea, which ranges from Texas to California and north to southern Canada. Burrowing Owls tend to be loosely colonial, and both the Florida populations and southerly populations of A. c. hypugaea from California to Texas are nonmigratory. To assess genetic structure, we examined 201 individuals from nine western and six Florida populations at seven highly variable microsatellite DNA loci. Mean gene diversity ([H.sub.exp]) was higher in the west than in Florida (0.539 and 0.341, respectively; P < 0.05). Populations within subspecies were essentially panmictic (A. c. floridana: [theta] = 0.038, [rho] = 0.014; A. c. hypugaea: [theta] = 0.014, [rho] = 0.009) and even genetic differentiation across subspecies was modest ([theta] = 0.051, [rho] = 0.014). Nevertheless, the western and Florida forms were easily distinguished by any of several criteria, such as allelic absences in Florida, assignment tests, and well-supported branches on the inferred phylogenetic tree. Genetic differentiation was at least twice as great in resident Florida ([theta] = 0.038) and California ([theta] = 0.021) populations as in migratory western populations ([theta] = 0.012), though 95% confidence intervals of theta estimates overlapped. We found no evidence of a genetic bottleneck that would result in evolutionary disequilibrium within subspecies. In the west, high observed heterozygosity values and evidence of gene flow suggest that population declines and patchy habitat, which currently imperil this species throughout much of its range, have not led to inbreeding or biologically meaningful genetic differentiation among the sampled populations. Received 21 December 2003, accepted 12 September 2004. Key words: Athene cunicularia, Burrowing Owl, genetic differentiation, microsatellite DNA markers, migration, philopatry.