抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Neandertals, the closest evolutionary relatives of present-day humans, lived in large parts of Europe and western Asia before disappearing 30,000 years ago. We present a draft sequence of the Neandertal genome composed of more than 4 billion nucleotides from three individuals. Comparisons of the Neandertal genome to the genomes of five present-day humans from different parts of the world identify a number of genomic regions that may have been affected by positive selection in ancestral modern humans, including genes involved in metabolism and in cognitive and skeletal development. We show that Neandertals shared more genetic variants with present-day humans in Eurasia than with present-day humans in sub-Saharan Africa, suggesting that gene flow from Neandertals into the ancestors of non-Africans occurred before the divergence of Eurasian groups from each other.

/pdf/a-draft-sequence-of-the-neandertal-genome-4nrrmzdsiy.pdf

A Draft Sequence of the Neandertal Genome

The microbiota - the collection of microorganisms that live within and on all mammals - provides crucial signals for the development and function of the immune system. Increased availability of technologies that profile microbial communities is facilitating the entry of many immunologists into the evolving field of host-microbiota studies. The microbial communities, their metabolites and components are not only necessary for immune homeostasis, they also influence the susceptibility of the host to many immune-mediated diseases and disorders. In this Review, we discuss technological and computational approaches for investigating the microbiome, as well as recent advances in our understanding of host immunity and microbial mutualism with a focus on specific microbial metabolites, bacterial components and the immune system.

/pdf/gut-microbiota-metabolites-and-host-immunity-1ie5ebhq2i.pdf

Gut microbiota, metabolites and host immunity

We present a DNA library preparation method that has allowed us to reconstruct a high-coverage (30×) genome sequence of a Denisovan, an extinct relative of Neandertals. The quality of this genome allows a direct estimation of Denisovan heterozygosity indicating that genetic diversity in these archaic hominins was extremely low. It also allows tentative dating of the specimen on the basis of “missing evolution” in its genome, detailed measurements of Denisovan and Neandertal admixture into present-day human populations, and the generation of a near-complete catalog of genetic changes that swept to high frequency in modern humans since their divergence from Denisovans.

https://science.sciencemag.org/content/sci/338/6104/222.full.pdf

A high-coverage genome sequence from an archaic Denisovan individual

High-throughput techniques based on restriction site-associated DNA sequencing (RADseq) are enabling the low-cost discovery and genotyping of thousands of genetic markers for any species, including non-model organisms, which is revolutionizing ecological, evolutionary and conservation genetics. Technical differences among these methods lead to important considerations for all steps of genomics studies, from the specific scientific questions that can be addressed, and the costs of library preparation and sequencing, to the types of bias and error inherent in the resulting data. In this Review, we provide a comprehensive discussion of RADseq methods to aid researchers in choosing among the many different approaches and avoiding erroneous scientific conclusions from RADseq data, a problem that has plagued other genetic marker types in the past.

/pdf/harnessing-the-power-of-radseq-for-ecological-and-1ienyx5mk2.pdf

Harnessing the power of RADseq for ecological and evolutionary genomics

Neandertals, our closest relatives, ranged across Europe and Southwest Asia before their extinction approximately 30,000 years ago. Green et al. (p. [710][1]) report a draft sequence of the Neandertal genome, created from three individuals, and compare it with genomes of five modern humans. The results suggest that ancient genomes of human relatives can be recovered with acceptably low contamination from modern human DNA. Because ancient DNA can be contaminated with microbial DNA, Burbano et al. (p. [723][2]) developed a target sequence capture approach to obtain 14 kilobases of Neandertal DNA from a fairly poorly preserved sample with a high microbial load. A number of genomic regions and genes were revealed as candidates for positive selection early in modern human history. The genomic data suggest that Neandertals mixed with modern human ancestors some 120,000 years ago, leaving traces of Neandertal DNA in contemporary humans.

 [1]: /lookup/doi/10.1126/science.1188021
 [2]: /lookup/doi/10.1126/science.1188046

/pdf/targeted-investigation-of-the-neandertal-genome-by-array-2zgzery3a9.pdf

Philipp L.F. Johnson

Papers

Targeted investigation of the Neandertal genome by array-based sequence capture