Chironomid assemblages from the uppermost sediments of 435 lakes spanning northern North America were compared to environmental parameters using direct gradient analysis. This large calibration set was merged from several previously developed regional datasets, and increases the number of modern analogues that are available for use for paleoenvironmental interpretations in this region. Air temperature explained the largest amount of variation in the chironomid assemblages with several other environmental factors accounting for statistical significant amounts of the remaining variance. A robust inference model for deriving past mean July air temperatures from subfossil chironomid assemblages was developed and applied to previously published paleoclimate reconstructions from the High-Arctic, Middle-Arctic, Boreal treeline, and Alpine regions of northern North America. The patterns of the temperature reconstructions from the combined dataset were generally similar to the original reconstructions, but with colder inferred temperatures reflecting the incorporation of a larger number of modern sites from colder climates in the combined dataset. This analysis demonstrated that the larger temperature gradient available in the new training set, when compared to the temperature gradients in the original training sets, provides a better estimation of chironomid-environment relationships. In particular, the optima and tolerances estimated using the larger, combined dataset should be more accurate, and therefore, improve midge-based paleoclimate reconstructions for northern North America. Despite the much larger spatial scale and greater associated environmental heterogeneity now incorporated in the combined dataset, this study suggests that in most cases the overarching constraint governing Electronic supplementary material The online version of this article (

Thirty-two taxa of chironomid larvae were collected from the sediments of 50 lakes from across the Canadian Arctic Islands. Most chironomid taxa living in the Arctic have wide distributions, with only one taxon, Abiskomyia, showing a clear geographic limitation in this region. Many of these taxa have habitat preferences, among which lake morphometry, pH, nutrients and temperature are important. Due to the complex environmental patterns in the Arctic, lakes in both the northern and southern portion of the Canadian Arctic Archipelago have warmer temperatures and the chironomid assemblages of these two regions resemble each other more than those of the intervening central islands. Chironomid diversity is lowest in the central arctic islands, primarily Devon and Cornwallis Island, where the combination of low nutrients and cold temperatures provide the most severe environment for chironomid survival.

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

No abstract

The rapidly rising cancer burden and mortality rate in Africa are in contrast to the increase in cancer survivorship in Europe and North America. Genomic medicine has contributed to the rise in survival and has facilitated precision cancer control. However, there is a shortage of African representation in genomic databases, even for cancers that disproportionately affect Africans. To improve this outlook and address research in genomics and genetics relevant to Africa and people of African descent, the African Organisation for Research and Training in Cancer (AORTIC), under the Research Committee's auspices, organised the Cancer Genomic Conference. The conference aimed to develop a roadmap for cancer genomics research to control the continent's increasing cancer burden. Presentations at the conference revealed that: (1) Africa is made up of a highly heterogeneous group of people with diverse ethnic groups, (2) Very few African countries have been the focus of cancer genomics research, (3) Cancer exacts a heavy burden on global populations across the African diaspora with obvious genetic variants and cancer disparities and (4) There are differences in the contribution of genetics by race or ancestry and these differences are likely due to evolutionary genetics, contextual factors and genomic architecture. The importance of data security, ethics and integrity of the African genomics data was emphasised. The implementation of the conference highlights will provide the bedrock for pharmacogenomics to guide treatment decisions for cancer in Africa. The conference concluded with the formation of an AORTIC Special Interest Group on cancer genomics. It is the goal of this group to drive the implementation of this Conference's outcomes.