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.

Ancient DNA is revealing new insights into the genetic relationship between Pleistocene hominins and modern humans. Nuclear DNA indicated Neanderthals as a sister group of Denisovans after diverging from modern humans. However, the closer affinity of the Neanderthal mitochondrial DNA (mtDNA) to modern humans than Denisovans has recently been suggested as the result of gene flow from an African source into Neanderthals before 100,000 years ago. Here we report the complete mtDNA of an archaic femur from the Hohlenstein–Stadel (HST) cave in southwestern Germany. HST carries the deepest divergent mtDNA lineage that splits from other Neanderthals ∼270,000 years ago, providing a lower boundary for the time of the putative mtDNA introgression event. We demonstrate that a complete Neanderthal mtDNA replacement is feasible over this time interval even with minimal hominin introgression. The highly divergent HST branch is indicative of greater mtDNA diversity during the Middle Pleistocene than in later periods.

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DNA hybridization‐capture techniques allow researchers to focus their sequencing efforts on preselected genomic regions. This feature is especially useful when analysing ancient DNA (aDNA) extracts, which are often dominated by exogenous environmental sources. Here, we assessed, for the first time, the performance of hyRAD as an inexpensive and design‐free alternative to commercial capture protocols to obtain authentic aDNA data from osseous remains. HyRAD relies on double enzymatic restriction of fresh DNA extracts to produce RNA probes that cover only a fraction of the genome and can serve as baits for capturing homologous fragments from aDNA libraries. We found that this approach could retrieve sequence data from horse remains coming from a range of preservation environments, including beyond radiocarbon range, yielding up to 146.5‐fold on‐target enrichment for aDNA extracts showing extremely low endogenous content (<1%). Performance was, however, more limited for those samples already characterized by good DNA preservation (>20%–30%), while the fraction of endogenous reads mapping on‐ and off‐target was relatively insensitive to the original endogenous DNA content. Procedures based on two instead of a single round of capture increased on‐target coverage up to 3.6‐fold. Additionally, we used methylation‐sensitive restriction enzymes to produce probes targeting hypomethylated regions, which improved data quality by reducing post‐mortem DNA damage and mapping within multicopy regions. Finally, we developed a fully automated hyRAD protocol utilizing inexpensive robotic platforms to facilitate capture processing. Overall, our work establishes hyRAD as a cost‐effective strategy to recover a set of shared orthologous variants across multiple ancient samples.

We measured autofluorescence of the macula with fluorophotometry to evaluate age-related changes in human retinal pigment epithelium. Examined in this study were 35 aphakic eyes of 25 patients, ranging in age from 52 to 87 years, after uneventful intracapsular cataract extraction and 21 normal phakic eyes of 20 patients, ranging in age from 9 to 29 years. Autofluorescence at the macula of aphakic eyes increased in an age-dependent manner (r = 0.514; p < 0.01) as follows: 15.0 ngEq/ml for the sixth decade (n = 1), 17.2 ± 4.2 for the seventh decade (n = 11), 21.3 ± 3.6 for the eighth decade (n = 16) and 24.6 ± 2.7 for the ninth decade (n = 7). We believe that the autofluorescence originates mainly from lipofuscin in the retinal pigment epithelium, and that the autofluorescence enhanced with age reflects the accumulation of lipofuscin.

Background: Overexpression of cyclin D1 and p53 protein has been reported in many types of malignant tumors. Objectives: We investigated whether cyclin D1 was detected immunohistochemically in various types of malignant tumors of the skin, comparable with p53 protein. Methods: Immunohistochemical staining of cyclin D1 and p53 protein was applied to squamous cell carcinoma, malignant melanoma and malignant fibrous histiocytoma and various kinds of benign skin tumors. Results: Cyclin D1 was positive only in malignant tumors at the same incidence as p53 protein. Conclusion: Cyclin D1 immunohistochemical staining may be a malignant marker for various skin tumors.

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Wild-type p53 accumulation induced by DNA damaging agents such as ultraviolet (UV) radiation, gamma-irradiation and drugs, may arrest the cell cycle until DNA damage is repaired. p21Waf1/Cip1 is a cyclin-dependent kinase (CDK) inhibitor induced by wild-type p53. CDK is activated by cyclin and progresses the cell cycle. On the other hand, CDK inhibitors inhibit CDK activity to arrest the cell cycle. Thus, p21Waf1/Cip1 is thought to mediate the signal of p53 induced by DNA damaging agents to arrest the cell cycle. p21Waf1/Cip1 is induced by wild-type, but not mutant p53. To investigate p21Waf1/Cip1 regulation by p53 in epidermis in vivo, immunohistochemical staining of p21Waf1/Cip1 and p53 were conducted in chronically sun-exposed normal epidermis and in neoplastic epidermis, p21Waf1/Cip1 expression was found to be coincident with the p53-positive regions or not coincident with the p53-positive regions in chronically sun-exposed normal epidermis, whereas there was only low or undetectable p21Waf1/Cip1 expression in any regions including the p53-positive regions of solar keratosis and squamous cell carcinoma of the skin. This suggests that wild-type p53 and p21Waf1/Cip1 may play a part in chronically sun-exposed normal epidermis response to UV exposure, whereas p21Waf1/Cip1 cannot be induced by mutated p53 in solar keratosis and squamous cell carcinoma of the skin.