Comparative quantitative investigations on brains of wild cavies (Cavia aperea) and guinea pigs (Cavia aperea f. porcellus). A contribution to size changes of CNS structures due to domestication

Intraspecific allometric calculations of the brain to body size relation revealed distinct differences between 127 (67; 60) ancestral wild cavies and 82 (37; 45) guinea pigs, their domesticated relatives. The dependency of both measures from one another remained the same in both animal groups but the brains of guinea pigs were by 14.22% smaller at any net body weight. Consistent with results in other species the domestication of Cavia aperea is also characterized by a decrease of brain size. Fresh tissue sizes of the five brain parts medulla oblongata, cerebellum, mesencephalon, diencephalon and telencephalon were determined for 6 cavies and 6 guinea pigs by the serial section method. Additionally the sizes of 16 endbrain structures and those of the optic tract, the lateral geniculate body and the cochlear nucleus were measured. Different decrease values resulted for all these structures concomitant with domestication as was calculated from the amount of total brain size decrease and average relative structure values in the wild as well as the domesticated brain. The size decrease of the entire telencephalon (−13.7%) was within the range of the mean overall reduction as similarly was the case for the total neocortex (−10.7%) whereas the total allocortex (−20.9%) clearly was more strongly affected. The size decrease of the olfactory bulb (−41.9%) was extreme and clearly higher than found for the secondary olfactory structures (around −11%). The primary nuclei of other sensory systems (vision, audition) were decreased to less extent (lateral geniculate: −18.1%; cochlear nucleus: −12.6%). Mass decreases of pure white matter parts were nearly twice as high in contrast to associated grey matter parts (neocortex white versus grey matter; tractus opticus versus lateral geniculate body). The relatively great decrease values found for the limbic structures hippocampus (−26.9%) and schizocortex (−25.9%) are especially notable since they are in good conformity with domestication effects in other mammalian species. The findings of this study are discussed with regard to results of similar investigations on wild and domesticated gerbils (Meriones unguiculatus), the encephalization of the wild form, the special and species-specific mode and duration of domestication and in connection with certain behavioral changes as resulted from comparative investigations in ethology, socio-biology, endocrinology and general physiology.     

The distribution, natural habitats and availability of wild cereals in relation to their domestication in the Near East: multiple events, multiple centres

In this article we examine the natural habitats and distribution of the six wild cereals: Triticum urartu (wild urartu wheat), T. boeoticum aegilopoides (single-grained wild einkorn), T. boeoticum thaoudar (two-grained wild einkorn), T. dicoccoides (wild emmer wheat), Secale spp. (wild ryes) and Hordeum spontaneum (wild barley). A comparison of late Pleistocene/early Holocene archaeobotanical assemblages in the Near East with present-day distributions of wild cereals shows a good correlation. The regional variation in the archaeobotanical cereal assemblages and the ensuing domestication provide evidence that different cereal species were domesticated independently in different areas. Some sites were not situated near wild cereal habitats and a few were located outside the limits of distribution, even accounting for moister climatic conditions. I argue here that current models which try to explain the shift to farming have tended to over-emphasize the effect of the Younger Dryas climatic change. First, it would have had only a minor effect on cereal availability. Secondly, agriculture appears to have been established after the Younger Dryas. Thirdly, there is no evidence for a single centre of origin; agriculture arose in widely separated geographic and climatic regions. And fourthly, agriculture depends on stable climatic conditions which were not established until after the Younger Dryas.     

圆红冬孢酵母利用生物乙醇废水-木薯粉水解液发酵产油

【目的】获得能够高效降解生物乙醇废水化学需氧量(COD)的圆红冬孢酵母菌株,评估废水初始COD浓度对驯化菌株生长的影响,将木薯粉生产微生物油脂和高浓度有机废水降解过程整合,以生物乙醇废水为水源制备生物乙醇废水-木薯粉水解液培养基,明确产油效率高、生物乙醇废水COD降解率高的初始还原糖浓度。【方法】采用在高浓度的生物乙醇废水中进行多次驯化的方法,获得能够适应废水环境的圆红冬孢酵母菌株;采用双酶水解法对加入乙醇废水中的木薯粉进行水解;采用重量法监测生物量浓度变化,采用酸热法提取油脂,重铬酸钾法监测COD,DNS法测定废水还原糖浓度,凯氏定氮法测定总氮,钼酸铵比色法测定总磷。【结果】通过驯化筛选得到一株能耐受高浓度生物乙醇废水的优势菌株Rhodosporidium toruloides D5。以未稀释的废水为培养基,驯化菌株的最终生物量浓度和COD降解率分别为3.8 g/L和75.0%。采用生物乙醇废水-木薯粉水解液发酵时,控制初始还原糖浓度低于30 g/L时,生物量浓度和油脂浓度随初始还原糖浓度的升高而升高,均在120 h时达到最高COD降解率,初始还原糖浓度对达到的最大COD降解率无明显影响,废水N、P去除率分别达到99%和92%以上。【结论】在未经稀释的高浓度生物乙醇废水中可获得较高的生物量浓度;采用高浓度生物乙醇废水-木薯粉水解液培养基发酵产油,初始还原糖浓度为30 g/L,可在保证高油脂产量的同时,实现废水COD的高效降解,有效回收利用废水中残余的N、P源,从而降低微生物油脂生产和废水处理成本,研究结果可为开发廉价微生物油脂生产技术提供有用的参考。     

Five thousand years of livestock in Britain

The introduction of livestock, including the rabbit and the fallow deer, to Britain is reviewed, and a summary is given of the history of husbandry arid selective breeding. The feeding or stock on foliage and its importance for survival through the winter is described. The meaning of domestication is discussed and ii is argued that there should be no separation between the old established breeds of livestock, park deer, and feral populations including Chillingham rattle, Soay sheep, and Bagot goats; all belong to the assemblage of large mammals that has created the landscape of the British Isles.     

Fearfulness in red junglefowl and domesticated White Leghorn chickens

It may be hypothesised that reduced fearfulness has been a major target of selection during domestication. We tested 20 domesticated White Leghorn (WL) chickens and their ancestors, red junglefowl (RJF), in four different fear tests (Open Field, Novel Object, Aerial Predator, and Fear for Humans). The tests were designed to measure reactions to different types of potentially fearful stimuli. The correlations between durations of the same four variables from each of the tests (Stand/sit alert, Locomotion, Fly/jump, and Vocalisation) were analysed with principal components analysis (PCA). In the PCA, 33.5% of the variation in responses was explained by a single factor, interpreted as a general fear factor. Higher scores on this were related to stronger fear reactions. Red junglefowl scored significantly higher than White Leghorns on this factor, and also had a longer latency to feed in the Fear of Humans-test, used as an independent measure of fear in the same tests. The results suggest that selection for low fearfulness has been an important element of domestication.     

爱羚:第一只家养成功的藏羚

藏羚 (Ｐａｎｔｈｏｌｏｐｓｈｏｄｇｓｏｎｉ)是青藏高原特有物种 ,隶属于偶蹄目牛科山羊亚科藏羚属[1～ 4 ] ,主要分布于中国境内的青海、西藏、新疆三省区交界处的高寒荒漠化草原、高寒草原和高寒草甸地区 ,海拔一般在 4 10 0～ 5 5 0 0ｍ之间 ,生存环境十分恶劣 ,目前已处于濒危状态。国际社会对藏羚羊的保护高度关注 ,但由于缺乏对该物种的科学认识 ,保护措施只能以反盗猎和打击藏羚羊绒及其制品的走私贸易为主[4 ] 。我们在青海省重大科技攻关项目和中国科学院知识创新工程项目的资助下 ,开展了藏羚羊种群生物学及保护措施的研究 ,并…     

Analysis of structural diversity in wolf-like canids reveals post-domestication variants

Background

Although a variety of genetic changes have been implicated in causing phenotypic differences among dogs, the role of copy number variants (CNVs) and their impact on phenotypic variation is still poorly understood. Further, very limited knowledge exists on structural variation in the gray wolf, the ancestor of the dog, or other closely related wild canids. Documenting CNVs variation in wild canids is essential to identify ancestral states and variation that may have appeared after domestication.

Results

In this work, we genotyped 1,611 dog CNVs in 23 wolf-like canids (4 purebred dogs, one dingo, 15 gray wolves, one red wolf, one coyote and one golden jackal) to identify CNVs that may have arisen after domestication. We have found an increase in GC-rich regions close to the breakpoints and around 1 kb away from them suggesting that some common motifs might be associated with the formation of CNVs. Among the CNV regions that showed the largest differentiation between dogs and wild canids we found 12 genes, nine of which are related to two known functions associated with dog domestication; growth (PDE4D, CRTC3 and NEB) and neurological function (PDE4D, EML5, ZNF500, SLC6A11, ELAVL2, RGS7 and CTSB).

Conclusions

Our results provide insight into the evolution of structural variation in canines, where recombination is not regulated by PRDM9 due to the inactivation of this gene. We also identified genes within the most differentiated CNV regions between dogs and wolves, which could reflect selection during the domestication process.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-465) contains supplementary material, which is available to authorized users.     

买麻藤科植物研究进展

买麻藤科植物是裸子植物中唯一的藤本植物,具有重要的理论研究和应用开发价值.全世界仅1属约40种,中国发现9种,分布于亚洲、非洲和南美洲的热带和亚热带地区;在理论研究方面,该科系统进化位置特殊,形态结构、化学成分和分子水平上的研究存在很大争议,仍没有解决其在裸子植物与被子植物间所处的进化位置;在应用研究方面,该科既是传统中药又富含芪类、生物碱和黄酮等活性成分,而且果实和叶片可食用;然而,在引种、驯化及培育方面研究薄弱,阻碍了该科资源的开发和利用.本文从资源分布、理论与应用研究以及开发利用等方面综述了买麻藤科植物研究进展,将为今后国内深入开展该科植物的相关研究奠定基础.     

褐飞虱共生解脂假丝酵母抗吡虫啉菌株的驯化

为进一步研究共生菌在褐飞虱对吡虫啉产生抗性中的生理生化机制,在稻田杀虫剂对褐飞虱共生解脂假丝酵母生长影响的基础上,选用不同吡虫啉浓度进行抗药性菌株的驯化。结果表明,褐飞虱共生解脂假丝酵母在不同吡虫啉浓度(2 000、1 000和500 mg/L)的固体培养基上继代培养,经过20代后2 000 mg/L培养基上的共生菌菌落数量,与未加吡虫啉的培养基上的菌落数量差异不明显,并且连续3代稳定后定为抗2 000 mg/L吡虫啉的共生菌菌株。在光镜下比较不同抗感吡虫啉菌株假菌丝的形态变化,发现抗吡虫啉菌株的假菌丝出现畸形,而且假丝变短,部分出现了膨大。     

A Phylogenetic Study of the Origin of the Domestic Pig Estimated from the Near-Complete mtDNA Genome

The near-complete pig mtDNA genome sequence (15,997 bp) was determined from two domestic pigs (one Chinese Meishan and one Swedish Landrace) and two European wild boars. The sequences were analyzed together with a previously published sequence representing a Swedish domestic pig. The sequences formed three distinct clades, denoted A, E1, and E2, with considerable sequence divergence between them (0.8–1.2%). The results confirm our previous study (based on the sequence of the cytochrome B gene and the control region only) and provide compelling evidence that domestication of pigs must have occurred from both an Asian and a European subspecies of the wild boar. We estimated the time since the divergence of clade A (found in Chinese Meishan pigs) and E1 (found in European domestic pigs) at about 900,000 years before present, long before domestication about 9000 years ago. The pattern of nucleotide substitutions among the sequences was in good agreement with previous interspecific comparisons of mammalian mtDNA; the lowest substitution rates were observed at nonsynonymous sites in protein-coding genes, in the tRNA and rRNA genes, while the highest rates were observed at synonymous sites and in the control region. The presence of Asian clade A in some major European breeds (Large White and Landrace) most likely reflects the documented introgression of Asian germplasm into European stocks during the 18th and 19th centuries. The coexistence of such divergent mtDNA haplotypes for 100+ generations is expected to lead to the presence of recombinant haplotypes if paternal transmission and recombination occur at a low frequency. We found no evidence of such recombination events in the limited sample studied so far. Received: 19 April 2000; Accepted: 15 November 2000