Genomic Evidence for Sensorial Adaptations to a Nocturnal Predatory Lifestyle in Owls

Owls (Strigiformes) evolved specific adaptations to their nocturnal predatory lifestyle, such as asymmetrical ears, a facial disk, and a feather structure allowing silent flight. Owls also share some traits with diurnal raptors and other nocturnal birds, such as cryptic plumage patterns, reversed sexual size dimorphism, and acute vision and hearing. The genetic basis of some of these adaptations to a nocturnal predatory lifestyle has been studied by candidate gene approaches but rarely with genome-wide scans. Here, we used a genome-wide comparative analysis to test for selection in the early history of the owls. We estimated the substitution rates in the coding regions of 20 bird genomes, including 11 owls of which five were newly sequenced. Then, we tested for functional overrepresentation across the genes that showed signals of selection. In the ancestral branch of the owls, we found traces of positive selection in the evolution of genes functionally related to visual perception, especially to phototransduction, and to chromosome packaging. Several genes that have been previously linked to acoustic perception, circadian rhythm, and feather structure also showed signals of an accelerated evolution in the origin of the owls. We discuss the functions of the genes under positive selection and their putative association with the adaptation to the nocturnal predatory lifestyle of the owls.

Reconstructed protein sequence evolution consistent with the evolution of C4 photosynthesis via a C2 ancestor in the Paniceae

The grass tribe Paniceae includes a monophyletic subclade of species, the MPC clade, which specialize in each of the three primary C4 sub-pathways NADP-ME, NAD-ME and PCK. The evolutionary history of C4 photosynthesis in this subclade remains ambiguous. Leveraging newly sequenced grass genomes and syntenic orthology data, we estimated rates of protein sequence evolution on ancestral branches for both core enzymes shared across different C4 sub-pathways and enzymes specific to C4 sub-pathways. While core enzymes show elevated rates of protein sequence evolution in ancestral branches consistent with a transition from C3 to C4 photosynthesis in the ancestor for this clade, no subtype specific enzymes showed similar patterns. At least one protein involved in photorespiration also showed elevated rates of protein sequence evolution in the ancestral branch. The set of core C4 enzymes examined here combined with the photorespiratory pathway are necessary for the C2 photosynthetic cycle, a previously proposed intermediate between C3 and C4 photosynthesis. The patterns reported here are consistent with, but not conclusive proof that, C4 photosynthesis in the MPC clade of the Paniceae evolved via a C2 intermediate.

Genetic Analysis of the Diversity and Origin of Hantaviruses in Peromyscus leucopus Mice in North America

ABSTRACT Nucleotide sequences were determined for the complete M genome segments of two distinct hantavirus genetic lineages which were detected in hantavirus antibody- and PCR-positive white-footed mice (Peromyscus leucopus) from Indiana and Oklahoma. Phylogenetic analyses indicated that although divergent from each other, the virus lineages in Indiana and Oklahoma were monophyletic and formed a newly identified unique ancestral branch within the clade of Sin Nombre-like viruses found in Peromyscus mice. Interestingly, P. leucopus-borne New York virus was found to be most closely related to the P. maniculatus-borne viruses, Sin Nombre and Monongahela, and monophyletic with Monongahela virus. In parallel, intraspecific phylogenetic relationships ofP. leucopus were also determined, based on the amplification, sequencing, and analysis of the DNA fragment representing the replication control region of the rodent mitochondrial genome. P. leucopus mitochondrial DNA haplotypes were found to form four separate genetic clades, referred to here as Eastern, Central, Northwestern, and Southwestern groups. The distinct Indiana and Oklahoma virus lineages were detected in P. leucopus of the Eastern and Southwestern mitochondrial DNA haplotypes, respectively. Taken together, our current data suggests that both cospeciation of Peromyscus-borne hantaviruses with their specific rodent hosts and biogeographic factors (such as allopatric migrations, geographic separation, and isolation) have played important roles in establishment of the current genetic diversity and geographic distribution of Sin Nombre-like hantaviruses. In particular, the unusual position of New York virus on the virus phylogenetic tree is most consistent with an historically recent host-switching event.

Dolichopodidae (Diptera) from Papua New Guinea. XIV. Paramedetera, a new genus in the Medeterinae

Paramedetera, gen. nov., is described on the basis of three species: P. papuensis, sp. nov., the type species from Papua New Guinea, P. sumatrensis, sp. nov., from the lowlands in West Sumatra, and P. orientalis (Hollis, 1964), comb. nov., from the highlands in West Sumatra. Paramedetera, gen. nov., is closely allied to Medetera, but is a more ancestral branch. It is phylogenetically situated between on one hand Corindia and Thrypticus and on the other hand Medetera and Dolichophorus.

Colombian Common and Lima Beans: Views on their Origin and Evolutionary Significance

<p>This article reviews the geographical distribution of wild common and lima beans in the Neotropics, their morphological and ecological attributes, and their biochemical and molecular variation along their ranges. These facts reveal the organization of the genetic diversity into three major gene pools, with one being considered ancestral, and additional subdivisions within the derived ones. The relationships between the ancestral branch and related species are discussed. Colombia appears to he more than a place of contact between gene pools of cultivated materials, but the transit place of the ancestral branches, and a possible place of domestication as well. </p><p> </p><p><strong>Los Fríjoles Colombianos Lima y Común: Puntos de Vista de su Origen y el Significado de su Evolución</strong></p><p>Se presenta una revisión de la distribución geográfica de las formas silvestres del frijol común y del frijol lima en el Neotrópico, de sus características morfológicas y ecológicas, y de la variación bioquímica y molecular a lo largo de esta distribución. Estos hechos muestran que la diversidad genética viene organizada en tres acervos o grupos de genes, uno de ellos siendo ancestral, y con subdivisiones adicionales dentro de los acervos derivados. Se discuten las relaciones filogenéticas entre este ramal ancestral y las especies afines. Más que lugar de contacto entre acervos de materiales cultivados, Colombia aparece como corredor biológico donde transitaron las ramas ancestrales, y como lugar de posible domesticación.</p><p> </p><p> </p>