The human occupation history of Southeast Asia (SEA) remains heavily debated. Current evidence suggests that SEA was occupied by Hòabìnhian hunter-gatherers until ~4000 years ago, when farming economies developed and expanded, restricting foraging groups to remote habitats. Some argue that agricultural development was indigenous; others favor the "two-layer" hypothesis that posits a southward expansion of farmers giving rise to present-day Southeast Asian genetic diversity. By sequencing 26 ancient human genomes (25 from SEA, 1 Japanese Jōmon), we show that neither interpretation fits the complexity of Southeast Asian history: Both Hòabìnhian hunter-gatherers and East Asian farmers contributed to current Southeast Asian diversity, with further migrations affecting island SEA and Vietnam. Our results help resolve one of the long-standing controversies in Southeast Asian prehistory.

High temperature (32 to 33°C) has been shown to reduce mortality in white spot syndrome virus (WSSV)-infected shrimps, but the mechanism still remains unclear. Here we show that in WSSV-infected shrimps cultured at 32°C, transcriptional levels of representative immediate-early, early, and late genes were initially higher than those at 25°C. However, neither the IE1 nor VP28 protein was detected at 32°C, suggesting that high temperature might inhibit WSSV protein synthesis. Two-dimensional gel electrophoresis analysis revealed two proteins, NAD-dependent aldehyde dehydrogenase (ALDH) and the proteasome alpha 4 subunit (proteasome ␣4), that were markedly upregulated in WSSV-infected shrimps at 32°C. Reverse transcription-PCR (RT-PCR) analysis of members of the heat shock protein family also showed that hsp70 was upregulated at 32°C. When aldh, proteasome ␣4, and hsp70 were knocked down by double-stranded RNA interference and shrimps were challenged with WSSV, the aldh and hsp70 knockdown shrimps became severely infected at 32°C, while the proteasome ␣4 knockdown shrimps remained uninfected. Our results therefore suggest that ALDH and Hsp70 both play an important role in the inhibition of WSSV replication at high temperature.White spot syndrome virus (WSSV) is a notorious pathogen in shrimp aquaculture. It has caused huge economic losses since it was first reported in 1992 in East Asia (6), and the virus is presently endemic in many parts of the world. WSSV is an ovoid to rod-shaped, enveloped, double-stranded DNA virus which belongs to the genus "Whispovirus" of the family Nimaviridae (35). The destructiveness of WSSV is partly due to its wide host range, which includes shrimp, crayfish, crabs, lobsters, and copepods (2, 9). In shrimps, mortality can reach 100% in 3 to 10 days after WSSV infection (20).Shrimps are exothermic animals, and unlike the case for endotherms, the body temperature of exotherms is directly susceptible to change depending on environmental conditions. Shrimp culture records show that outbreaks of WSSV are less likely to occur during warm seasons (29, 39), and there is other evidence suggesting that high temperature might protect shrimps from WSSV. Vidal et al. (34) reported that temperatures of 32 to 33°C can significantly reduce mortality in WSSVinfected shrimps. Other research has suggested that the water temperature needs to be maintained at 33°C for only 12 or 18 h per day in order to delay or reduce mortality in WSSV-infected shrimps (26). However, even though the use of warm water for shrimp cultivation has generally been accepted as beneficial by the shrimp culture industry and is already applied in some commercial shrimp farms, the exact mechanisms that underlie this phenomenon are still unknown. Granja et al. (12) proposed that high temperature might increase cell apoptosis and that this would help to prevent the replication of WSSV. However, apoptosis is no longer thought to be a principal protective factor against WSSV in shrimps (10, 40). Others have suggested that high tempera...

The long process of rice domestication likely started 10,000–8,000 years ago in China, and the pre-existing hunter-gatherer communities gradually adopted more sedentary lifestyles with the dependence of rice agricultural economies. The archeological evidence builds a strong case for the first domestication of rice to Oryza sativa centered in the Middle-Lower Yangtze Valley during the early Holocene. The genetic evidence identifies the main ancestor of O. sativa was O. rufipogon, however, this now occurs naturally south of the Yangtze where its distribution is limited by summer temperatures and mean annual temperature. The mismatch between occurrence of ancestors and presumed sites of early cultivation leads to a number of hypotheses. These include that first domestication actually took place further south, such as in the Pearl River valley but archeological evidence is currently lacking for this. Or domestication took place, when O. rufipogon had a more extensive natural range in the past. Early to mid-Holocene palaeoclimate reconstructions show that the East Asian Summer Monsoon was more active in the early Holocene and estimates show that the temperature requirements for O. rufipogon were met for a substantial area of northeast China at the time. This would mean that earliest known domestication sites and presumed ancestor distribution coincided for several millennia. Thus early records of rice farming in Henan and Shandong were easily accommodated by early to mid Holocene climates.

No abstract

No abstract