Host plant variation in mortality of the leaf-folding sawfly on the arroyo willow

Abstract. 1. We tested the hypothesis that survival and sources of mortality of the leaf-folding sawfly ( Phyllocolpa sp.) varied significantly among host plants of the arroyo willow ( Salix lasiolepis Bent ham).
2. Survival of the leaf folder differed among field and potted willows in a common environment in two of three cases, and sources of mortality differed among plants in four of five cases.
3. Egg mortality differed among field plants but not among the potted willow plants.
4. Larval mortality and parasitism differed among field and potted willows in 2 years, and appeared to be compensatory mortality sources.
5. Leaf folder density among plants was not generally correlated with percentage of leaf folds with no egg (galls formed but no subsequent oviposition), percentage survival, or percentage mortality, indicating a general lack of density dependence.
6. The proportion of folds with no egg oviposited differed significantly among field and potted plants, and was only correlated with survival or sources of mortality in one of three years.
7. The data support the hypothesis that host plant genotype affects the interaction of the leaf folder with its natural enemies, and thus represents a three trophic level interaction.     

Studies on theStellaria longipes complex (Caryophyllaceae): Isozyme variability and the relationship betweenStellaria longipes andS. longifolia

Genetic variation within and the relationship betweenStellaria longipes Goldie andS. longifolia Muhl. were studied. Ten enzyme systems were assessed in eight natural populations ofS. longipes (25 loci) and three ofS. longifolia (20 loci) using starch and polyacrylamide gel electrophoresis. Patterns of population differentiation corresponded to geographic distance. There was no evidence that polyploidS. longipes had greater electrophoretic variability than diploidS. longipes. The isozyme data confirmed extensive population differentiation in these species and, within that context, a relatively close relationship betweenS. longipes andS. longifolia. It was postulated that diploids of these two species might be the progenitors of tetraploidS. longipes.     

DNA “fingerprints” and paternity ascertainment in chimpanzees (Pan troglodytes)

Highly variable regions of DNA are found in a wide diversity of organisms and are typically composed of alleles consisting of a variable number of tandem repeats (VNTRs) of a short core sequence. DNA fingerprinting probes are VNTR probes that simultaneously detect a large number of similar VNTRs in the target DNA. The highly polymorphic pattern observed in a DNA fingerprint allows resolution of questions concerning individual identification. M13 phage was used to fingerprint captive chimpanzees for paternity ascertainment. Although the probability of band sharing among captive chimps appears to be higher than among some other reported captive and feral animal populations, the probe is highly useful and can be expected to become more widely used in the genetic management of captive populations.     

中国昆明小鼠亚群蛋白质多态性的研究

本文报道采用电泳技术对北京、上海、长春3市的4个中国昆明小鼠(简称KM)实验群体中24个蛋白质标志研究的结果,与我国1981年从美国引进的NIH小鼠进行比较,显示出:(1)KM小鼠亚群间等位基因组成无明显差异,它们间遗传距离为0.008—0.027,与群体封闭时间成正相关;(2)4个KM小鼠群体间聚类分析发现S:KM群体为特殊一类,该结果与KM亚群间下颌骨分析结果相符;(3)KM与Swiss来源的NIH小鼠群体间在E(?)-3、Es-10、Got-2、Glo-1、Gpt-1、和Mpi-1座位上的等位基因组成存在显著差异,它们之间的遗传距离平均值为0.131±0.011,证实中国KM小鼠为非Swiss来源的一个亚种。     

The genetic structure of a primate species: Rhesus macaques and other Cercopithecine monkeys

Among rhesus macaques (Macaca mulatta)and other cercopithecine monkeys, social groups occupying adjacent home ranges (i.e., members of the same local population) exchange individuals and genes and thus exhibit marked genetic similarities. To assess the degree to which this pattern extends beyond the local population, the genetic structure of M. mulattaand six other primate species was determined using Nei’s (1973) gene-diversity analysis. The genetic similarities seen among social groups in the Dunga Gali population of M. mulatta (Melnick et al.,1984a) can be seen over the entire species range. Comparison of these results with the structures of other similarly organized primate species indicates that (1) the average social group contains most of its local population’s genetic diversity, (2) the average local population contains the majority of the genetic diversity found in the region to which it belongs, and (3) the proportion of species gene diversity found in the average regional population varies substantially between species. Genetic homogeneity within local and regional populations is probably the product of gene flow. The application of a number of analytical models of selection and gene flow strongly suggests that gene flow, genetic drift, and zoogeography offer a more parsimonious and plausible explanation for interspecific variation in regional differentiation than does stabilizing selection.     

Gene survival in the Asian wild horse (Equus przewalskii): I. Dependence of gene survival in the calgary breeding group pedigree

The joint probability distribution of the number of distinct (not identical by descent) genes from each founder of the Equus przewalskii population that survive in the five horses of the Calgary Zoological Gardens breeding group has been calculated. The dependence structure of this distribution is investigated, and informative marginal distributions are given, among them the distributions of the genetic contributions of each founder to the Calgary horses and the distribution of wild-type genes in these horses. The dependence pattern is found to be complex; there is no substitute for exact calculation of the full joint probability distribution of numbers of surviving genes. Probabilities of gene survival give a more complete summary of the genetic structure of a set of individuals than is provided by more routine measures such as heterozygosity or founder contributions. The feasibility of computing these probabilities for small groups of current individuals descended from few founders via long and complex pedigrees, provides a new approach to assessing such groups, and could be used also in selecting animals to form the founder stock of propagules for future reintroduction programs.     

Zinc tolerance in populations ofDeschampsia cespitosa (Gramineae) beneath electricity pylons

Patterns of zinc tolerance were examined in eightDeschampsia cespitosa (L.)Beauv. populations from normal and zinc-contaminated soils, using solution culture methods. Zinc-tolerant populations have evolved beneath pylons, and their tolerance patterns (degree, variance, heritability) vary. Tolerance is genetically based in all of them. In contrast to the cases of other species previously reported, some within-population differences are considerable, and may be due to both heterogeneity of the soils zinc contents, various gene combinations and gene recombinations between genotypes. One control population contains many tolerant plants, an original result which is discussed.     

Gene variation and gene flow inOrchis morio (Orchidaceae) from Italy

Data are presented on genetic variation at 27 enzyme loci of the Green-Winged orchid,Orchis morio, in 18 population samples from Italy. The existence in Italy of two subspecies, i.e. subspp.morio andpicta, is not supported by allozyme data. No genetic heterogeneity was found betweenmorio-like andpicta-like samples and specimens. Moreover, morphological transition between the two forms was observed in different Italian populations. The parameters of genetic variability estimated forO. morio populations are consistent with those found among monocotyledon plants, and among those outcrossing, animal-pollinated and with wind-dispersed seeds. Genetic diversity of ItalianO. morio is mostly within populations. Correspondingly, low values of interpopulational genetic distance were found. This appears to be due to high levels of gene flow, which were estimated with different methods. The lack ofO. longicornu from Italian samples, as well as of any hybrid withO. morio (F₁, backcrossed or recombinant individuals) is demonstrated on the basis of genetic data. It is concluded that recurrent reports ofO. longicornu from Italy are due to confusion withO. morio or with otherOrchis species.