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While few places on earth have been as deeply impacted by the human-horse relationship as the steppes of Mongolia and eastern Eurasia, gaps in the archaeological record have made it strikingly difficult to trace when and how the first domestic horses were integrated into ancient societies in this key region of the world. Recently, organic materials preserved in melting mountain ice have emerged as a key source of archaeological insight into the region's deep past. Newly-identified artefacts recovered from melting snow and ice in the Altai Mountain range of western Mongolia (including metal artefacts, skeletal remains, and hoof fragments) provide archaeological evidence for the use of horses at high altitudes from the Bronze Age through the 20th century. Direct radiocarbon dating and genomic sequencing demonstrate the presence of Przewalski's horse in the region during the early second millennium BCE, suggesting that this taxon may have once foraged at high altitudes frequented by human hunters. Importantly, directly-dated remains of horse hoof trimmings provide some of the oldest direct evidence of horse transport in the Eastern Steppe as early as the 14th century BCE, and suggest a role for high-mountain hunting in the innovation of reliable mounted riding. [ABSTRACT FROM AUTHOR]

Horses revolutionized human history with fast mobility1. However, the timeline between their domestication and their widespread integration as a means of transport remains contentious2–4. Here we assemble a collection of 475 ancient horse genomes to assess the period when these animals were first reshaped by human agency in Eurasia. We find that reproductive control of the modern domestic lineage emerged around 2200 bce, through close-kin mating and shortened generation times. Reproductive control emerged following a severe domestication bottleneck starting no earlier than approximately 2700 bce, and coincided with a sudden expansion across Eurasia that ultimately resulted in the replacement of nearly every local horse lineage. This expansion marked the rise of widespread horse-based mobility in human history, which refutes the commonly held narrative of large horse herds accompanying the massive migration of steppe peoples across Europe around 3000 bce and earlier3,5. Finally, we detect significantly shortened generation times at Botai around 3500 bce, a settlement from central Asia associated with corrals and a subsistence economy centred on horses6,7. This supports local horse husbandry before the rise of modern domestic bloodlines.Analyses of 475 ancient horse genomes show modern horses emerged around 2200 bce, coinciding with sudden expansion across Eurasia, refuting the narrative of large horse herds accompanying earlier migrations of steppe peoples across Europe. [ABSTRACT FROM AUTHOR]

Ancient DNA preservation in subfossil specimens provides a unique opportunity to retrieve genetic information from the past. As ancient DNA extracts are generally dominated by molecules originating from environmental microbes, capture techniques are often used to economically retrieve orthologous sequence data at the population scale. Post‐mortem DNA damage, especially the deamination of cytosine residues into uracils, also considerably inflates sequence error rates unless ancient DNA extracts are treated with the USER enzymatic mix prior to library construction. While both approaches have recently gained popularity in ancient DNA research, the impact of USER‐treatment on capture efficacy still remains untested. In this study, we applied hyRAD capture to eight ancient equine subfossil specimens from France (1st–17th century CE), including horses, donkeys and their first‐generation mule hybrids. We found that USER‐treatment could reduce capture efficacy and introduce significant experimental bias. It differentially affected the size distribution of on‐target templates following capture with two distinct hyRAD probe sets in a manner that was not driven by differences in probe sizes and DNA methylation levels. Finally, we recovered unbalanced proportions of donkey‐specific and horse‐specific alleles in mule capture sequence data, due to the combined effects of USER‐treatment, probe sets and reference bias. Our work demonstrates that while USER‐treatment can improve the quality of ancient DNA sequence data, it can also significantly affect hyRAD capture outcomes, introducing bias in the sequence data that is difficult to predict based on simple molecular probe features. Such technical batch effects may prove easier to model and correct for using capture with synthetic probes of controlled sizes and diversity content. [ABSTRACT FROM AUTHOR]

Domestication of horses fundamentally transformed long-range mobility and warfare1. However, modern domesticated breeds do not descend from the earliest domestic horse lineage associated with archaeological evidence of bridling, milking and corralling2–4 at Botai, Central Asia around 3500 bc3. Other longstanding candidate regions for horse domestication, such as Iberia5 and Anatolia6, have also recently been challenged. Thus, the genetic, geographic and temporal origins of modern domestic horses have remained unknown. Here we pinpoint the Western Eurasian steppes, especially the lower Volga-Don region, as the homeland of modern domestic horses. Furthermore, we map the population changes accompanying domestication from 273 ancient horse genomes. This reveals that modern domestic horses ultimately replaced almost all other local populations as they expanded rapidly across Eurasia from about 2000 bc, synchronously with equestrian material culture, including Sintashta spoke-wheeled chariots. We find that equestrianism involved strong selection for critical locomotor and behavioural adaptations at the GSDMC and ZFPM1 genes. Our results reject the commonly held association7 between horseback riding and the massive expansion of Yamnaya steppe pastoralists into Europe around 3000 bc8,9 driving the spread of Indo-European languages10. This contrasts with the scenario in Asia where Indo-Iranian languages, chariots and horses spread together, following the early second millennium bc Sintashta culture11,12.Analysis of 273 ancient horse genomes reveals that modern domestic horses originated in the Western Eurasian steppes, especially the lower Volga-Don region. [ABSTRACT FROM AUTHOR]

The increased use of biostimulants in conventional agriculture and organic farming requires the implementation of rapid tests to determine their effectiveness in enhancing plant growth and protection against abiotic stresses. However, their innocuity to plant health has rarely been demonstrated. We used the Vicia faba Micronucleus Assay, as described by the standard AFNOR EN ISO 29200(2020-05) to reveal biostimulant, genotoxic and cytotoxic effects of four commercialized wood-based products by comparing mitotic indices and micronucleus frequencies with respect to the controls. Neither genotoxicity, as measured by micronucleus frequency (MN), nor cytotoxicity, assessed by Mitotic index counts, was observed. Additionally, one of these stimulants (BHS®) conferred protective effects against contaminants (maleic hydrazide or lead nitrate). We describe that plotting micronuclei frequency against mitotic indices allows discrimination between cytotoxic/genotoxic effects from growth levels. Vicia faba experiments were successfully transposed to other agronomical important crops such as corn and sunflower. This technique can be valuable to industrials, to assess growth, potential cytoxicity and genotoxicity effects of any new biostimulant or organic. [ABSTRACT FROM AUTHOR]