The relationships of the Yellow-breasted Chat (Icteria virens) and the alleged slowdown in the rate of macromolecular evolution in birds

The taxonomic relationships of the Yellow-breasted Chat (Icteria virens) have been uncertain since its discovery more than 200 years ago. Although usually considered to be a New World wood warbler (Parulini) it possesses structural and behavioral characteristics that seem aberrant in comparison with the typical members of that group. The relationships of Icteria were investigated by comparing its single-copy DNA sequences with those of other New World nine-primaried oscines and representatives of other oscine families, using the technique of DNA-DNA hybridization. The data indicate that Icteria is a paruline warbler and it should continue to be included within that group. The study of Icteria provided the basis for an examination of the suggestion by several authors that the proteins of birds and, by extension, their DNAs, evolve more slowly than do those of other animals. Evidence is presented indicating that the alleged differences are due, at least in part, to differences in the human perception of the boundaries of taxonomic categories in birds versus most other organisms. Birds are taxonomically oversplit at all supraspecific levels, but small, nocturnal mammals and other groups are probably overlumped at all levels. The lack of equivalence between the taxonomic categories of birds and those of other animals results in an erroneous evaluation of their rates of macromolecular evolution. DNA hybridization data indicate that the vireos (Vireoninae) are not closely related to the wood warblers, or to other New World nine-primaried oscines. We have shown elsewhere that the vireos are members of a large, varied corvine assemblage

Divergence of the single-copy DNA sequences of the Western Grebe (Aechmophorus occidentalis) and Clark’s Grebe (A. clarkii), as indicated by DNA-DNA hybridization

Single-copy nuclear DNA sequences of individuals of Aechmophorus occidentalis and A. ciarkii were compared by DNA-DNA hybridization. In each of three experimental sets the average thermal stability of homoduplex and within-species DNA-DNA hybrids did not differ, but the between-species DNA-DNA hybrids dissociated at an average temperature 0.57°C below the median melting temperature of homoduplex and within-species hybrids. The difference was highly significant in all three sets. The median DNA sequence distance between A. occidentalis and A. clarkii is comparable to such distances between other closely related congeneric species

A comparative study of the egg white proteins of non-passerine birds

The starch gel electrophoretic patterns of the egg white proteins of 816 species of non-passerine birds were studies…

Phylogeny and Classification of Birds : A Study in Molecular Evolution

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1082 MONTHLY WEATHER REVIEW VOLUME 131 Improved Skill for the Anomaly Correlation of Geopotential Heights at 500 hPa � 2003 American Meteorological Society

This paper addresses the anomaly correlation of the 500-hPa geopotential heights from a suite of global multimodels and from a model-weighted ensemble mean called the superensemble. This procedure follows a number of current studies on weather and seasonal climate forecasting that are being pursued. This study includes a slightly different procedure from that used in other current experimental forecasts for other variables. Here a superensemble for the �2 of the geopotential based on the daily forecasts of the geopotential fields at the 500hPa level is constructed. The geopotential of the superensemble is recovered from the solution of the Poisson equation. This procedure appears to improve the skill for those scales where the variance of the geopotential is large and contributes to a marked improvement in the skill of the anomaly correlation. Especially large improvements over the Southern Hemisphere are noted. Consistent day-6 forecast skill above 0.80 is achieved on a day to day basis. The superensemble skills are higher than those of the best model and the ensemble mean. For days 1–6 the percent improvement in anomaly correlations of the superensemble over the best model are 0.3, 0.8, 2.25, 4.75, 8.6, and 14.6, respectively, for the Northern Hemisphere. The corresponding numbers for the Southern Hemisphere are 1.12, 1.66, 2.69, 4.48, 7.11, and 12.17. Major improvement of anomaly correlation skills is realized by the superensemble at days 5 and 6 of forecasts. The collective regional strengths of the member models, which is reflected in the proposed superensemble, provide a useful consensus product that may be useful for future operational guidance. 1