Project description:Analyses of ancient DNA typically involve sequencing the surviving short oligonucleotides, and aligning to genome assemblies from related, modern species. Here, we report that skin from a female woolly mammoth (†Mammuthus primigenius) which died 52,000 years ago retained its ancient genome architecture. We use PaleoHi-C to map chromatin contacts and assemble its genome, yielding twenty-eight chromosome-length scaffolds. Chromosome territories, compartments, loops, Barr bodies, and inactive-X chromosome (Xi) superdomains persist. The active and inactive genome compartments in mammoth skin more closely resemble Asian elephant skin than other elephant tissues. Our analyses uncover new biology. Differences in compartmentalization reveal genes whose transcription was potentially altered in mammoths vs. elephants. Mammoth Xi has a tetradic architecture, not bipartite like human and mouse. We hypothesize that, shortly after this mammoth’s death, the sample spontaneously freeze-dried in the Siberian cold, leading to a glass transition that preserved subfossils of ancient chromosomes at nanometer scale.
Project description:The investigation of archaeological samples, which are of inestimable value, requires minimally destructive or non-destructive sampling techniques. One of the most promising and recent non-invasive techniques is known under the acronym EVA, an ethylene vinyl acetate film which avoids contamination and proteins damages. The present work reports the results of the metaproteomic analysis performed on the middle part of a trunk, and on the portion of a trunk tip tissue of two different woolly mammoths some 40000 years’ old. In particular, proteins were extracted by applying EVA (Ethylene-Vinyl Acetate) films to the surface of these tissues belonging to two Mammuthus primigenus specimens, discovered in two regions located in the Russian Far East, and then investigated via a shotgun MS-based approach. This approach allowed to obtain two interesting results: i) an indirect description of the habitat of these two mammoths, and ii) an improved sequence characterization of the alpha-1 type I collagen (col1a1), the major component of type I collagen. Sequence characterization of the col1a1 highlighted some differences between M. primigenius and other Proboscidea together with the identification of two potentially diagnostic amino acidic mutations that could be used to reliably distinguish the Mammuthus primigenius respect to the other two genera of elephantids (i.e. Elephas and Loxodonta), and the extinct American mastodon (i.e. Mammut americanum). The results were validated through the level of deamidation and other diagenetic chemical modifications of the sample peptides, which were used to discriminate the “original” endogenous peptides from contaminant ones.
Project description:During ripening of fruits stored under low temperatures, a number of physiological alterations which are manifested in a reduction of juice content take place, resulting in the apparition of woolly fruits. Modifications in cell wall structure during the ripening process are proposed to be key to determine the decreasing of juice content in woolly fruits. Under the assumption that changes in relative abundance of genes related to cell wall metabolism would be involved in woolliness development, in this work we present an analysis of the expression of multiple genes, which serves as an approximation to uncover the mechanisms behind this physiological alteration. The expression of 847 genes was examined using macroarrays hybridizations. Membranes were hybridized with 32P-labeled cDNAs synthesized from mRNAs of juice and woolly peaches. The results showed that 67.5% of the clones (n = 573) fulfilled all filter criteria and they were selected for sequence analysis. Our analysis indicate that 45% of transcripts which present a consistent expression level in all biological replicates are activated exclusively in juice condition, and only 15% in woolly fruits. In the resting 40% (transcripts common to both conditions,) only 5% presents an abundance increase in woolly samples. Keywords: Analysis of physiological disorder in peaches
Project description:The goal of this experiment was to confirmed a suspected translocation of ~3MB of chrX to chrY in the widely-used Four Core Genotypes mouse model.