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Until recently, the causal agent of Botryosphaeria canker was assumed to differ from that causing ring rot on fruit and warts on branches on apple trees in China and East Asia. However, recent research documented that Botryosphaeria dothidea caused both disease symptoms on apple. Inoculations with strains isolated from cankers and warts on branches were conducted to investigate symptom progression caused by B. dothidea and conditions inducing the two symptom types. The results confirmed that both cankers and warts are caused by B. dothidea. Warts are the results of hyperplasia and suberization of bark tissues induced by fungal infection, whereas cankers result from the rapid growth of hyphae from inside warts, lenticels, or wounds. Resistance to B. dothidea exists in living apple branches. When a living branch is infected via lenticels, the pathogen induces proliferation and suberization of cortical cells that restricts the growth and expansion of the hyphae, leading to warts. However, under certain stress conditions such as drought, the hyphae inside host tissues expand rapidly and kill cortical cells, leading to canker development. Host resistance may recover during active growth periods, which suppresses or even stops rapid expansion of the hyphae, leading to the intermediate symptom of canker warts. Abiotic factors, such as drought or high temperature in early spring, can result in rapid extension of colonized hyphae in branches and conversion of warts to cankers. Preventing this transition can be an important measure in managing Botryosphaeria canker on apple. [ABSTRACT FROM AUTHOR]

The prehistoric peopling of East Asia by modern humans remains controversial with respect to early population migrations. Here, we present a systematic sampling and genetic screening of an East Asian-specific Y-chromosome haplogroup (O3-M122) in 2,332 individuals from diverse East Asian populations. Our results indicate that the O3-M122 lineage is dominant in East Asian populations, with an average frequency of 44.3%. The microsatellite data show that the O3-M122 haplotypes in southern East Asia are more diverse than those in northern East Asia, suggesting a southern origin of the O3-M122 mutation. It was estimated that the early northward migration of the O3-M122 lineages in East Asia occurred ∼25,000–30,000 years ago, consistent with the fossil records of modern humans in East Asia. [ABSTRACT FROM AUTHOR]