Impact of commercial RNA extraction methods on the recovery of human RNA sequence data from archival fixed tissues.

Archival fixed tissues hold key insights into the evolutionary history of RNA viruses and the associated host immune response, yet access to the RNA sequence data is limited by a lack of robust methods for RNA extraction and sequence retrieval from these tissue types. Here we compared three commercial RNA extraction techniques (bead, column, and phase-based) on five fixed human brain tissues done in triplicate, that have been stored for up to 43 years. We found that for this sample set, bead-based extractions captured longer molecules and yielded a greater proportion of unique reads when aligned to the human genome, than did column and phase-based extraction methods.

Combining C and N from bone and dentine in marine mammal palaeoecological research: insights from toothed whales.

Stable carbon (C) and nitrogen (N) isotopic compositions of bone and dentine collagen extracted from museum specimens have been widely used to study the paleoecology of past populations. Due to possible systematic differences in stable isotope values between bone and dentine, dentine values need to be transformed into bone-collagen equivalent using a correction factor to allow comparisons between the two collagen sources. Here, we provide correction factors to transform dentine C and N values into bone-collagen equivalent for two toothed whales: narwhal and beluga.

Acidification does not alter the stable isotope composition of bone collagen.

In this study, we compared the elemental and isotopic composition of modern and ancient bone samples pre-treated using different demineralization agents with acidic and neutral pH. The purpose of our research was to examine if demineralization using a mineral acid such as hydrochloric acid (HCl) significantly alters the N and C values of bone collagen. Evidence from the elemental and amino acid composition of the samples were incorporated alongside isotopic compositions to provide a holistic view of the effect of demineralization agents on the composition of bone collagen.