枇杷属植物等位酶遗传变异及品种基因型指纹

利用超薄平板微型聚丙烯酰胺凝胶的等电聚焦电泳技术,对国家枇杷种质资源圃所收集保存的113个枇杷（Eriobotrya japonica Lindl．）品种（或株系）和4个野生近缘种[栎叶枇杷（E．prinoides Rehd．et Wils．）、大渡河枇杷（E．prinoides var．daduheensis H．Z．Zhang）、齿叶枇杷（E．serrata Vidal．）、大瑶山枇杷（E．dayaoshanensis Chen．）],共117份材料进行了等位酶遗传变异分析。在12个酶系中共检测到24个清晰位点和59个等位基因,多态位点为21个,位点最大等位基因数为5,体现出枇杷丰富的遗传种质多样性;X^2分析表明等位基因频率在不同产地品种群间存在明显差异,在用于分析的19个多态位点中,有15个位点达到显著或极显著水平;且不同的种材料拥有各自特有等位基因,如Dia-1^c,Dia-2^b,Dia-3^b只存在于大瑶山枇杷中,Est-2^b,Est-3^a只存在于大渡河枇杷中,Idh-1^d仅出现于枇杷品种荔枝枇杷中,体现了枇杷物种间的遗传组成差异;利用11个酶系统22个位点的53个等位基因所构建的枇杷品种（株系）等位酶基因型指纹可以将113个枇杷品种中的111个完全区分,各品种均有自己独特的等位酶基因型指纹,虽然进一步的分析表明,目前所研究的酶系统位点和等位基因变异与枇杷品种果实园艺性状变异间缺乏关联,但等位酶标记仍然不失为枇杷品种鉴别的一种有用工具。     

Are Polyommatus hispana and Polyommatus slovacus bivoltine Polyommatus coridon (Lepidoptera: Lycaenidae)? The discriminatory value of genetics in taxonomy

Taxonomic confusion exists in several sibling species groups. The Polyommatus coridon species complex (Chalk Hill Blues) serves as a model group of sibling species in which genetic analyses provide suitable means for taxonomic clarification. We studied the allozyme patterns of the two described bivoltine species of this complex, Polyommatus hispana and Polyommatus slovacus, and compared them to the two genetic lineages of the univoltine P. coridon. P. hispana is well distinguished from P. coridon (genetic distance: 0.081), and most probably is a sibling species that has evolved during glacial isolation on the Iberian Peninsula. P. slovacus is genetically indistinguishable from the eastern, Pontic–Mediterranean lineage of P. coridon; therefore we suggest that it represents a local bivoltine population only. Since the spring generation of P. slovacus was much less common than the summer generation and showed less genetic diversity, it is probable that uni-/bivoltinism is a dimorphism affecting only part of the whole population. We suggest that the higher genetic diversity of the second generation may be a consequence of gene flow from adjacent single-brooded populations.     

葫芦苏铁遗传多样性的等位酶分析

采用等位酶技术,分析了葫芦苏铁5个居群的遗传多样性。分析6个酶系统,共获得了13个基因位点, 结果表明:葫芦苏铁具有较高水平的遗传变异性,多态位点百分率(P)为56．9％,等位基因平均数A=1.62,等 位基因多样性指数Ho=0.105,He=0．164,居群杂合体过量的位点为50％。居群遗传结构分析表明,大部分 遗传变异(93．6％)存在于居群内(FST=0．064),居群间分化程度甚微。根据葫芦苏铁的居群遗传结构式样并 结合相关研究,提出了就地保护所有居群,迁地保护从东一、王下和水田三个大居群取样的保护策略。     

The genetic consequence of differing ecological demands of a generalist and a specialist butterfly species

Many studies aim at testing the impact of recent fragmentation on the genetic diversity and connectivity of populations, while some species do exist naturally in fragmented landscapes because of their habitat requirements. Therefore, it is important to look at the genetic signatures of species occurring in naturally fragmented landscapes in order to disentangle the effect of fragmentation from the effect of habitat requirements. We selected two Nymphalid butterflies for this purpose. While Melanargia galathea is a common butterfly in flower-rich meadows, Melitaea aurelia is closely connected to calcareous grasslands, thus being historically fragmented due to its ecological demands. For the analysis of the genetic response on these opposed patterns, we analysed 18 allozyme loci for 789 individuals (399 individuals of M. galathea and 390 individuals of M. aurelia) in a western German study region with adjacent areas in Luxemburg and northeastern France. Both species showed similarly low genetic differentiations among local populations (M. galathea: F _ST 3.3%; M. aurelia: F _ST 3.6%), both combined with a moderate level of inbreeding. Isolation-by-distance analysis revealed a significant correlation for both species with similar amounts of explained variances (M. galathea: r ² = 27.8%; M. aurelia: r ² = 28.5%). Most parameters of genetic diversity were higher in M. galathea than in M. aurelia, but the latter species had a considerably higher amount of rare or locally restricted genes; the differing ecological demands are thus reflected in these differences. Both species thus seem to be genetically well suited to their respective ecological requirements. In the light of conservation genetics, we deduce that highly fragmented populations are not necessarily prone to extinction. The extinction risk might be linked to the life history of an organism and its population genetic structure.     

Effect of allozyme heterozygosity on basal and induced levels of heat shock protein (Hsp70), in juvenile Concholepas concholepas (Mollusca)

Organisms cope physiologically with extreme temperature by producing heat shock proteins (HSPs). Expression of Hsp70 enhances thermal tolerance and represents a key strategy for ectotherms to tolerate elevated temperature in nature. Synthesis of these proteins, together with other physiological responses to elevated temperatures, increases energy demands. A positive association between multiple and single locus heterozygosity (MLH and SLH, respectively) and individual fitness has been widely demonstrated. In molluscs, MLH can decrease routine metabolic rates and improve energetic status. Juvenile Concholepas concholepas live in the intertidal zone and are constantly exposed to temperature fluctuations. Thus, these young individuals are exposed both to thermal risks and the large metabolic costs required to cope with thermal stress. We evaluated the effects of allozyme MLH and SLH on basal (control animals) and induced (stressed animals) levels of the Hsp70 in juveniles C. concholepas. Juveniles (n = 400) were acclimated at 16 °C for 2 weeks; then 100 animals were exposed to 24 °C (stress) and 100 were kept at 16 °C (control) for 2 and 7 days. The variability of 20 loci was analyzed by starch gel electrophoresis. For SLH effects we used 7 polymorphic loci. We quantified expression of Hsp70 by Western blot analyses. Hsp70 expression increased markedly (~ 90%) with temperature. We found a positive association between MLH and basal and induced levels of Hsp70 in the 2-day exposure experiment. Regardless of temperature, Hsp70 levels increased with MLH (r² = 0.7 and 0.9, for basal and induced levels, respectively) reaching maximal levels in juveniles with intermediate and high MLH levels (2 and 3 loci), and decreasing slightly (but not significantly) in juveniles with highest MLH (≥ 4 heterozygous loci). However, after 7 days of exposure to thermal stress, less heterozygous juveniles attained the same levels of Hsp70 than more heterozygous juveniles. Given the faster increment of Hsp70 in C. concholepas juveniles with intermediate-high levels of MLH, these individuals could be less affected by thermal stress in the intertidal zone. We found an association between specific loci genotype and higher Hsp70 levels (basal or induced). In comparison to homozygous juveniles, heterozygous juveniles for several loci showed higher Hsp70. However, these associations were not for the same loci in juveniles exposed to high temperature for 2 and 7 days. This suggests genotypic variation at some allozyme loci could be more important in the period of initial response to high temperature and others can be more important in the response to the chronic temperature stress.     

广西区西南桦天然居群遗传多样性的研究

 以采自广西区11个西南桦(Betula alnoides)天然居群的种子培育出的幼苗为材料,取其嫩叶开展21种酶系统的水平切片淀粉凝胶电泳实验,运用作者改进的Tris-马来酸提取缓冲液 (含30%PVP 40 000和1%2-巯基乙醇),筛选出AMP(氨基肽酶Aminopeptidase)、FBA(果糖二磷酸酶Fructose-bisphosphate aldolase)、GDH(谷氨酸脱氢酶Glutamate dehydrogenase)、G6PD(6-磷酸葡萄糖脱氢酶Glucose-6-phosphate dehydrogenase)、IDH(异柠檬酸脱氢酶Isocitrate dehydrogenase)、MDH(苹果酸脱氢酶Malate dehydrogenase)、PGD(6-磷酸葡萄糖酸脱氢酶Phosphogluconate dehydrogenase)、PGI(磷酸葡萄糖异构酶Phosphoglucoisomerase)、PGM(磷酸葡萄糖变位酶Phosphoglucomutase)和SKD(莽草酸脱氢酶Shikimate dehydrogenase)等10种酶,获得了清晰且可重复的酶谱。通过谱带遗传分析确定了15个位点,其中有6个单态位点,9个多态位点 (0.95标准),具40个等位基因。在居群水平上,西南桦的多态位点百分数 (P) 为55.2%,平均每个位点的等位基因数 (A) 为2.00,平均预期杂合度 (He) 为0.204。均超过Hamrick (1992)等提出的远交风媒木本植物的平均值(53.0%,184%和0154),表明西南桦的遗传变异水平高。在11个西南桦居群内,实际杂合度 (Ho)均高于预期杂合度,出现杂合子过量,可能存在利于杂合子的自然选择。西南桦遗传多样性与地理位置相关不显著。居群2 (靖西地州)、5 (平果海城)、9 (田林者苗) 包含绝大部分的等位基因,而且具较高的遗传多样性,应加以保护和管理,作为其基因资源就地保存的基地。本研究解决了以西南桦嫩叶为材料进行等位酶分析的关键技术,为进一步开展西南桦乃至桦木属树种的遗传结构和遗传多样性等提供了技术基础;同时掌握了西南桦天然居群的遗传多样性现状,为其有效保护和合理经营以及西南桦的遗传改良提供了理论依据。     

短葶飞蓬云南三个种群的核型与等位酶分析

通过核型和等位酶分析,对短葶飞蓬（Erigeron breviscapus)种群遗传结构进行了较全面的研究。研究材料来自丽江,昆明,邱北,核型分析表明,这3个种群都为二倍体种群（2n=2x=18),以丽江种群为例,短葶飞蓬核型为2n=2x=18=6m 10sm(2SAT) 2st,10种酶的等位酶分析表明,短葶飞蓬的遗传变异存在于种群内,种群间遗传一致度高（I=0.9172),遗传距离小（D=0.0876),遗传距离与空间距离大致成正相关。     

Large effective population sizes and high levels of gene flow between subpopulations of Lilium cernuum (Liliaceae)

The Baekdudaegan, a mountain range that runs north to south along the Korean Peninsula, has been suggested to harbor important glacial refugia for boreal and temperate plant species. A series of allozyme-based genetic studies supports this trend. A large effective population size (N_e) is suggested as one of major factors contributing to maintaining moderate or high levels of within-population genetic variation in these plant species. To test this hypothesis, we examined the levels and patterns of allozyme diversity, tested recent bottlenecks, and estimated recent migration rates in 10 subpopulations (collected within a distance of ca. 640 m) of the boreal Lilium cernuum at Mt. Deokhang, in the central part of the Baekdudaegan. We found high levels of within-population genetic variation as well as a low between-population genetic differentiation (H_e = 0.206 and F_ST = 0.019). Based on the F_ST estimate and mean recent migration rate, we approximately calculated a total effective population size of 508 across 10 subpopulations. Consistent with this, we found no evidence of recent bottlenecks in the subpopulations. This study reveals that subpopulations of L. cernuum at Mt. Deokhang are effectively large (on the order of hundreds), and that high levels of gene flow occur among them, probably due to the species' high potential for seed dispersal. These demographic and life-history traits, coupled with its high levels of genetic diversity, suggests that this cold-adapted species would have found large refugial areas in these mountains (i.e., macrorefugia) during the Last Glacial Maximum.     

中国板栗居群间等位酶基因频率的空间分布

中国板栗21个自然群间等位酶遗传变异的空间自相关分析及F－统计分析结果表明：其多数等位基因频率在居群间呈随机分布模式,缺乏一定的空间结构;而部分等位基因表现为渐变或双向渐变的非随机分布模式,又具有特定空间结构。中国板栗遗传变异空间结构模式的形成可能是长距离基因流、自然气候、人类活动、地理距离隔离等诸因素综合作用的结果。文中还就居群等位基因分布格局的成因进行了讨论：在第四纪冰川后,中国板栗以长江流域中下游的孑遗中心为起点,等位基因分别沿着向北和向南的不同方向迁移形成现在的居群结构;季风气候和人类活动干扰是削弱居群分化的主要因素,而基于环境梯度的选择,是形成由北向南渐变分布的原因。     

A fluvial population of Cottus pollux (middle-egg type) from the Honmyo River, Kyushu Island, Japan

 Specimens of the Cottus pollux species' group collected from the upper part of the Honmyo River, Nagasaki Prefecture, Japan, were subjected to morphological and allozyme analyses to place them into one of the recognized valid taxa, viz. small-egg type (SE type), middle-egg type (ME type), or large-egg type (LE type). They were identified as ME type on the basis of specific morphological characteristics, such as laterally depressed cross-sectional shape at posterior half of the body and deep caudal peduncle, and by having a diagnostic allozyme allele (MEP ^* 54). This ME-type population is the first recorded from Kyushu Island, Japan. An ecological survey of the population revealed that females spawned larger eggs (2.8–3.2 mm in diameter) than those of other amphidromous populations, from which well-developed yolk-sac larvae of about 8.0 mm TL were hatched out. In addition, ME-type specimens collected on 25 and 26 May 2001 included 15 sex-unknown juveniles ranging from 18.8 to 30.2 mm SL, suggesting that they represented larvae hatched out on a nearby spawning ground, with no experience of downstream migration into Isahaya Bay. This observation strongly suggests that the ME-type population in the Honmyo River has a fluvial lifestyle, being different from other amphidromous populations. The former population may have arisen from an amphidromous ancestor through changes in egg size and early ontogenetic development. Received: February 25, 2002 / Revised: May 21, 2002 / Accepted: June 17, 2002 Acknowledgments We thank Professor M. Azuma, Nagasaki University, for his kind guidance of our field survey in the Honmyo River and Dr. G.S. Hardy, Thames, New Zealand, for correcting the English. Thanks are also offered to Mrs. Y. Miyajima and Y. Masaoka, Kyushu Branch of Construction and Technology Institute Co., for their helpful cooperation in the field survey. Drs. H. Sakai, National Fisheries University and Y. Yamazaki, Toyama University, and Mrs. N. Okabe and Y. Suzuki of Yamagata Prefecture are thanked for their help in sample collection. This work was partly supported by a Grant-in-Aid (No. 13660171) from the Japan Ministry of Education, Culture, Sports, Science and Technology to A. Goto. Correspondence to:Akira Goto