The evolution of phylogeographic data sets.

Empirical phylogeographic studies have progressively sampled greater numbers of loci over time, in part motivated by theoretical papers showing that estimates of key demographic parameters improve as the number of loci increases. Recently, next-generation sequencing has been applied to questions about organismal history, with the promise of revolutionizing the field. However, no systematic assessment of how phylogeographic data sets have changed over time with respect to overall size and information content has been performed. Here, we quantify the changing nature of these genetic data sets over the past 20 years, focusing on papers published in Molecular Ecology. We found that the number of independent loci, the total number of alleles sampled and the total number of single nucleotide polymorphisms (SNPs) per data set has improved over time, with particularly dramatic increases within the past 5 years. Interestingly, uniparentally inherited organellar markers (e.g. animal mitochondrial and plant chloroplast DNA) continue to represent an important component of phylogeographic data. Single-species studies (cf. comparative studies) that focus on vertebrates (particularly fish and to some extent, birds) represent the gold standard of phylogeographic data collection. Based on the current trajectory seen in our survey data, forecast modelling indicates that the median number of SNPs per data set for studies published by the end of the year 2016 may approach ~20,000. This survey provides baseline information for understanding the evolution of phylogeographic data sets and underscores the fact that development of analytical methods for handling very large genetic data sets will be critical for facilitating growth of the field.

The maillard reaction for sunlight protection.

During seven months of a clinical trial in spring, summer, and fall, 30 UVA/B/Soret band-photosensitive patients used sequential topical applications of dihydroxyacetone (DHA) followed by naphthoquinone only at bedtime and received excellent photoprotection without a single therapeutic failure or loss of any patient to follow-up. Eighteen of the 30 patients extended the limits of their photoprotection repeatedly over a seven-month period to tolerate without sunburns six to eight hours of midday sunlight under all kinds of occupational and recreational environmental conditions. Previously, the use of 3% DHA topically in earlier studies gave only a sun protection factor (SPF) of 3. In this reanalysis of the original notes of a previous clinical study of the melanoidins produced by DHA followed by naphthoquinone in the keratin layers of the epidermis of minimally pigmented Caucasian photosensitive patients, it is determined that these patients received a minimal UVB photoprotection of SPF 18 or more. This represents at least a sixfold amplification of the UVB photoprotective effect over the use of only dihydroxyacetone in the Maillard reaction.