The identification of sequence boundaries is the key point for sequence stratigraphic classification. Both the higher-order sequences and the units within the sequences are bounded with the key sediments or isochronou...The identification of sequence boundaries is the key point for sequence stratigraphic classification. Both the higher-order sequences and the units within the sequences are bounded with the key sediments or isochronous surfaces. Eight sequences can be divided in the whole Permo-Carboniferous strata （the Shiqianfeng Formation is not included）, which is from the Benxi Formation, Taiyuan Formation, Shanxi Formation, Xiashihezi Formation, Wanshan Section, and Kuishan Section to the Xiaofuhe Section. Also, different system tracts （Iowstand system tract, transgression system tract and highstand system tract） and some parasequences can be recognized in each sequence. Parasequence analysis was on the basis of the division of the base-level cycle. The base-level cycle was mainly identified according to the change of the water area, which was reflected by the depositional sequence. The physical characteristic of the strata was reflected by the well log. It was supplied by the test of the minerals and rocks and the analysis of the micro-element in the lab. The paleogeographic characteristic of the Iowstand system tract in the sequence Ⅵ is that the east-north part takes the river system as its feature; the south part is the lake system, the river channel spreads from north to south, and the area of the flooding plain is great. The paleogeographic characteristic of the water-transgressive system tract is that the range of the lake in the south extended distinctively, the range of the river channel in the east reduced. The coastal shallow lake deposit is the main characteristic in the water-transgressive system tract. The paleogeographic characteristic of the highstand system tract is similar to the one of the Iowstand system tract.展开更多
Rice (Oryza sativa) was first domesticated in the lower and middle Yangtze regions of China, and rice remains have been found in many Chinese archaeological sites. Until now, only phenotypic archeobotanical evidence, ...Rice (Oryza sativa) was first domesticated in the lower and middle Yangtze regions of China, and rice remains have been found in many Chinese archaeological sites. Until now, only phenotypic archeobotanical evidence, such as the spikelet bases of ancient grains, has been used to speculate on the domestication process and domestication rate of rice. In this study, we sequenced 4 genomic segments from rice remains in Tianluoshan, a site of the local Hemudu Neolithic culture in the low Yangtze and two other archaeological sites (~2400 and 1200 BC, respectively). We compared our sequences with those of the current domesticated and wild rice (O. rufipogon) populations. At least two genotypes were found in the remains from each site, suggesting a heterozygotic state of the rice seeds. One ancient genotype was not found in the current domesticated population and might have been lost. The rice remains belonged to the japonica group, and most if not all were japonica-type, suggesting that the remains might be at an early stage of indica-japonica divergence or an indica-japonica mixture. We also identified sequences with significant similarity to those from species of Sapindales, Zygophyllales, and Brassicales, which is consistent with the identification of other plant remains in the Tianluoshan site and the common rice field weeds such as mustards in southern China.展开更多
Ancient DNA data have supported a sister relationship between woolly rhinoceros and extant Sumatran rhinoceros.This relationship has been used to explore the divergent times for the woolly rhinoceros from their relati...Ancient DNA data have supported a sister relationship between woolly rhinoceros and extant Sumatran rhinoceros.This relationship has been used to explore the divergent times for the woolly rhinoceros from their relatives.Complete and partial ancient DNA sequences of the mitochondrial cytochrome b(cyt b)gene were retrieved from bones of the late Pleistocene Coelodonta antiquitatis excavated from northern and northeastern China.The newly obtained sequences together with the European and northern Asian Coelodonta antiquitatis sequences from GenBank were used to estimate the evolutionary divergence time.Phylogenetic analyses showed the exchange of genetic information between the Chinese individuals and Coelodonta antiquitatis of north Asia,which also indicated a more recent evolutionary timescale(3.8–4.7 Ma)than previous molecular estimations(17.5–22.8 or 21–26 Ma)for woolly rhinoceros based on the fossil calibration of outgroups.This new timescale was more consistent with the fossil record of the earliest known genus Coelodonta.展开更多
基金Supported by the Nation's National Science Foundation of China(40742010)
文摘The identification of sequence boundaries is the key point for sequence stratigraphic classification. Both the higher-order sequences and the units within the sequences are bounded with the key sediments or isochronous surfaces. Eight sequences can be divided in the whole Permo-Carboniferous strata （the Shiqianfeng Formation is not included）, which is from the Benxi Formation, Taiyuan Formation, Shanxi Formation, Xiashihezi Formation, Wanshan Section, and Kuishan Section to the Xiaofuhe Section. Also, different system tracts （Iowstand system tract, transgression system tract and highstand system tract） and some parasequences can be recognized in each sequence. Parasequence analysis was on the basis of the division of the base-level cycle. The base-level cycle was mainly identified according to the change of the water area, which was reflected by the depositional sequence. The physical characteristic of the strata was reflected by the well log. It was supplied by the test of the minerals and rocks and the analysis of the micro-element in the lab. The paleogeographic characteristic of the Iowstand system tract in the sequence Ⅵ is that the east-north part takes the river system as its feature; the south part is the lake system, the river channel spreads from north to south, and the area of the flooding plain is great. The paleogeographic characteristic of the water-transgressive system tract is that the range of the lake in the south extended distinctively, the range of the river channel in the east reduced. The coastal shallow lake deposit is the main characteristic in the water-transgressive system tract. The paleogeographic characteristic of the highstand system tract is similar to the one of the Iowstand system tract.
基金the National Basic Research Program of China (2011CB109306)the National High Technology Research and Development Program of China (2006AA10A102)+1 种基金partially by a pilot program (2007DKA20Z90)a DAAD Fellowship
文摘Rice (Oryza sativa) was first domesticated in the lower and middle Yangtze regions of China, and rice remains have been found in many Chinese archaeological sites. Until now, only phenotypic archeobotanical evidence, such as the spikelet bases of ancient grains, has been used to speculate on the domestication process and domestication rate of rice. In this study, we sequenced 4 genomic segments from rice remains in Tianluoshan, a site of the local Hemudu Neolithic culture in the low Yangtze and two other archaeological sites (~2400 and 1200 BC, respectively). We compared our sequences with those of the current domesticated and wild rice (O. rufipogon) populations. At least two genotypes were found in the remains from each site, suggesting a heterozygotic state of the rice seeds. One ancient genotype was not found in the current domesticated population and might have been lost. The rice remains belonged to the japonica group, and most if not all were japonica-type, suggesting that the remains might be at an early stage of indica-japonica divergence or an indica-japonica mixture. We also identified sequences with significant similarity to those from species of Sapindales, Zygophyllales, and Brassicales, which is consistent with the identification of other plant remains in the Tianluoshan site and the common rice field weeds such as mustards in southern China.
基金Yang Hong was supported by a short term Guest Professor through the sponsorship of China University of Geosciences in Wuhansupported by National Basic Research Program of China(Grant No.2011CB808800)+1 种基金National Natural Science Foundation of China(Grant Nos.40672006,40902008)"111"Project of Chinese State Administration of Foreign Experts Affairs(Grant No.B08030)
文摘Ancient DNA data have supported a sister relationship between woolly rhinoceros and extant Sumatran rhinoceros.This relationship has been used to explore the divergent times for the woolly rhinoceros from their relatives.Complete and partial ancient DNA sequences of the mitochondrial cytochrome b(cyt b)gene were retrieved from bones of the late Pleistocene Coelodonta antiquitatis excavated from northern and northeastern China.The newly obtained sequences together with the European and northern Asian Coelodonta antiquitatis sequences from GenBank were used to estimate the evolutionary divergence time.Phylogenetic analyses showed the exchange of genetic information between the Chinese individuals and Coelodonta antiquitatis of north Asia,which also indicated a more recent evolutionary timescale(3.8–4.7 Ma)than previous molecular estimations(17.5–22.8 or 21–26 Ma)for woolly rhinoceros based on the fossil calibration of outgroups.This new timescale was more consistent with the fossil record of the earliest known genus Coelodonta.
