Serial Monogamy as Polygyny or Polyandry?

Applications of sexual selection theory to humans lead us to expect that because of mammalian sex differences in obligate parental investment there will be gender differences in fitness variances, and males will benefit more than females from multiple mates. Recent theoretical work in behavioral ecology suggests reality is more complex. In this paper, focused on humans, predictions are derived from conventional parental investment theory regarding expected outcomes associated with serial monogamy and are tested with new data from a postreproductive cohort of men and women in a primarily horticultural population in western Tanzania (Pimbwe). Several predictions derived from the view that serial monogamy is a reproductive strategy from which males benefit are not supported. Furthermore, Pimbwe women are the primary beneficiaries of multiple marriages. The implications for applications of sexual selection theory to humans are discussed, in particular the fact that in some populations women lead sexual and reproductive lives that are very different from those derived from a simple Bateman-Trivers model.     

STRUCTURALLY PRESERVED FOSSIL PLANTS FROM ANTARCTICA III. PERMIAN SEEDS

Small, anatomically preserved gymnospermous seeds are detailed from late Permian age silicified specimens collected in the Beardmore Glacier region of Antarctica. The seeds are platyspermic with prominent, sarcotestal wings and a simple pollen chamber. The integument consists of a narrow endotesta, a two-parted sclerotesta and a complex sarcotesta. In mature seeds, the nucellus is present as a papery layer, separated from the endotesta by a nucellar and endotestal cuticle. Cellular megagametophytes are present in many of the seeds and commonly contain two archegonia. A multicellular embryo is present within each archegonium. The embryos are at a similar stage of development and provide evidence of simple polyembryony in these seeds. Although the affinities of the seeds are not presently known, they are discussed in the context of other seeds described from Gondwana deposits, as well as the known flora from the Beardmore Glacier area.     

5 S and 5.8 S ribosomal RNA sequences and protist phylogenetics

More than 100 5 S 5.8 S rRNA sequences from protists, including fungi, are known. Through a combination of quantitative treeing and special consideration of "signature' nucleotide combinations, the most significant phylogenetic implications of these data are emphasized. Also, limitations of the data for phylogenetic inferences are discussed and other significant data are brought to bear on the inferences obtained. 5 S sequences from red algae are seen as the most isolated among eukaryotics. A 5 S sequence lineage consisting of oomycetes, euglenoids, most protozoa, most slime molds and perhaps dinoflagellates and mesozoa is defined. Such a lineage is not evident from 5.8 S rRNA or cytochrome c sequence data. 5 S sequences from Ascomycota and Basidiomycota are consistent with the proposal that each is derived from a mycelial form with a haploid yeast phase and simple septal pores, probably most resembling present Taphrinales. 5 S sequences from Chytridiomycota and Zygomycota are not clearly distinct from each other and suggest that a major lineage radiation occurred in the early history of each. Qualitative biochemical data clearly supports a dichotomy between an Ascomycota-Basidiomycota lineage and a Zygomycota-Chytridiomycota lineage.     

Woodland small mammal population ecology in Britain: a preliminary review of the Mammal Society survey of Wood Mice Apodemus sylvaticus and Bank Voles Clethrionomys glareolus, 1982–87

The Mammal Society has co-ordinated a population survey of Wood Mice Apodemus sylvaticus and Bank Voles Clethrionomys glareolus in 13 0.81 -hectare sites in Britain. Numbers of mice and voles live-trapped using standard methods were collated every May/June and November/December from 1982 to 1987. The data were analysed with results from four independent studies in England and the corresponding assessments of tree seed crop size. Wood Mouse numbers are usually higher in winter than in summer but Bank Vole fluctuations are less regular. In deciduous woodland, Wood Mouse mean relative densities are significantly greater in the winter and the following summer after a good seed crop than after a poor one; rates of population change from summer to winter are significantly higher when a good seed crop falls. Bank Vole relative densities are significantly greater in the summer following a good seed crop than after a poor one, and rates of change from winter to summer are significantly higher. In Wood Mouse populations, tests for density dependence suggest that it is strong from summer to winter but absent from winter to summer; in Bank Voles weaker density dependence is present in both halves of the year. Thus, Wood Mouse numbers are regulated in autumn but are also influenced by seed crop size in winter and the following summer; Bank Vole numbers are less strongly regulated during both autumn and spring and are influenced by seed crop size in the following summer. Evidence is presented suggesting that populations of each species in deciduous woodlands are synchronized over the country in summer and that Wood Mice are also synchronized in winter; highs and lows tend to coincide between different sites. The yield of tree seed is shown to vary significantly from year to year and may be the cause of the synchrony, but weather effects may also be involved.     

Impact of gene flow from cultivated beet on genetic diversity of wild sea beet populations

Gene flow and introgression from cultivated plants may have important consequences for the conservation of wild plant populations. Cultivated beets (sugar beet, red beet and Swiss chard: Beta vulgaris ssp. vulgaris) are of particular concern because they are cross-compatible with the wild taxon, sea beet (B.vs. ssp. maritima). Cultivated beet seed production areas are sometimes adjacent to sea beet populations; the numbers of flowering individuals in the former typically outnumber those in the populations of the latter. In such situations, gene flow from cultivated beets has the potential to alter the genetic composition of the nearby wild populations. In this study we measured isozyme allele frequencies of 11 polymorphic loci in 26 accessions of cultivated beet, in 20 sea beet accessions growing near a cultivated beet seed production region in northeastern Italy, and 19 wild beet accessions growing far from seed production areas. We found one allele that is specific to sugar beet, relative to other cultivated types, and a second that has a much higher frequency in Swiss chard and red beet than in sugar beet. Both alleles are typically rare in sea beet populations that are distant from seed production areas, but both are common in those that are near the Italian cultivated beet seed production region, supporting the contention that gene flow from the crop to the wild species can be substantial when both grow in proximity. Interestingly, the introgressed populations have higher genetic diversity than those that are isolated from the crop. The crop-to-wild gene flow rates are unknown, as are the fitness consequences of such alleles in the wild. Thus, we are unable to assess the long-term impact of such introgression. However, it is clear that gene flow from a crop to a wild taxon does not necessarily result in a decrease in the genetic diversity of the native plant.     

Distinguishing between population bottleneck and population subdivision by a Bayesian model choice procedure

Although most natural populations are genetically subdivided, they are often analysed as if they were panmictic units. In particular, signals of past demographic size changes are often inferred from genetic data by assuming that the analysed sample is drawn from a population without any internal subdivision. However, it has been shown that a bottleneck signal can result from the presence of some recent immigrants in a population. It thus appears important to contrast these two alternative scenarios in a model choice procedure to prevent wrong conclusions to be made. We use here an Approximate Bayesian Computation (ABC) approach to infer whether observed patterns of genetic diversity in a given sample are more compatible with it being drawn from a panmictic population having gone through some size change, or from one or several demes belonging to a recent finite island model. Simulations show that we can correctly identify samples drawn from a subdivided population in up to 95% of the cases for a wide range of parameters. We apply our model choice procedure to the case of the chimpanzee (Pan troglodytes) and find conclusive evidence that Western and Eastern chimpanzee samples are drawn from a spatially subdivided population.     

Composition and Structure of Protein Bodies and Spherosomes Isolated from Ungerminated Seeds of Sorghum bicolor (Linn.) Moench

Protein bodies and spherosomes have been isolated from mature seeds of Sorghum bicolor (Linn.) Moench by a procedure which successfully disrupts the protein starch complex in the grain. Protein bodies from whole grain are 68% protein and have a distinct border and a monolithic appearance. Those from embryo are 95% protein and have diffuse borders, vacuoles, and appear very granular. Aleurone tissue protein bodies are 46% protein with a structure similar to those from embryo, but possibly are composed of a protein carbohydrate mixture. Spherosomes from all sources are quite similar in composition and structure. They have an average composition of 27% protein, 12% phosphorus, and 8.6% metals. Microscopically, they appear as small vesicles bounded by a wall which is probably composed of protein and the potassiummagnesium salt of phytic acid.     

Relatedness of penicillin-binding protein 1a genes from different clones of penicillin-resistant Streptococcus pneumoniae isolated in South Africa and Spain.

Penicillin-resistant strains of Streptococcus pneumoniae have been common in South Africa and Spain for several years. Multilocus enzyme electrophoresis identified one clone of capsular type 6B which was prevalent in Spain and another clone of type 23F that was present in both countries. Genes for penicillin-binding proteins (PBPs) in penicillin-resistant strains are often mosaics where parts of the pneumococcal genes are replaced by homologous genes from other species. We have compared the mosaic structures of the PBP 1a genes from the two clones as well as from genetically distinct South African isolates. Four classes of mosaic PBP 1a genes were found that contained blocks of sequences divergent by 6-22% from those of sensitive genes; two classes contained sequences coming from more than one external source. Data are presented showing that the PBP 1a genes from the 23F and the 6B clone are related, and that the two PBP 1a genes from the South African isolates are also related. We suggest that the type 23F clone originated in Spain prior to distribution into other continents.     

Relationships between European and North American biological species ofArmillaria mellea

Pairings of monosporous isolates from five European and ten North American biological species ofArmillaria reveal that certain species from Europe are interfertile with certain species from North American. All other pairings between species are intersterile. These pairings of isolates derived from different continents reveal three interactions not observed in earlier studies with isolates exclusively from one continent or the other. One, pairings from species demonstrated to be interfertile have a reduced frequency of compatibility, i.e., some determinant, in addition to mating type, affects the compatibility of specific pairings. Two, the pairing of isolates from intersterile species occasionally results in an unexplained reduction in growth in one or both members of the pairing. Three, in a single case, members of a species from one continent are compatible with members oftwo different intersterile species from the other continent. In fact, individual strains from one European species are compatible with members of two rigorously intersterile North American species.     

Evaluation of Holocene pollen records from the Romanian Plain

This study is a critical review of pollen analyses carried out on Holocene sequences from 15 sites in and near the Romanian Plain. Three sites come from natural sediments, 10 sites are from anthropogenic deposits and two are from both anthropogenic and natural settings. The general reconstruction is of a steppe-forest-steppe vegetation through the Holocene. The nature of the deposits, however, casts doubts on this reconstruction. Deposits of archaeological sites generally yield pollen spectra that are influenced by human activities and thus unsuitable for vegetation reconstructions. Loess deposits are also unfavorable for pollen preservation because of high pH and porosity. Consequently, pollen spectra from loess deposits are strongly biased by selective pollen destruction. Research and experiments carried out by several authors suggest that spectra dominated by Asteraceae, Poaceae, Chenopodiaceae or Pinus pollen in soils and loess are a result of selective pollen destruction, especially if low pollen concentrations, progressive pollen deterioration or high frequencies of deteriorated or unidentifiable pollen are evidenced. The fact that pollen records from the Romanian Plain come from loess, alkaline peat or archaeological sites reduces their reliability for reconstructions of vegetation. The vegetation history of similar regions in Hungary, Bulgaria and Turkey suggests that early Holocene steppe vegetation was gradually replaced by forest or forest-steppe vegetation in the late Holocene. Records from lake sediments are required to find out whether the Holocene vegetation history of the Romanian Plain was similar.     

北美外来植物中原产东亚类群的学名考证

作者在整理北美外来入侵植物中发现一些起源(或主要分布)于东亚植物的学名,在北美乃至欧洲使用非常混乱.本文特将有关重要类群整理出来,包括异名、原产地、北美的分布以及必要的讨论等.     

The origin of protein and fatty yolk in Rana pipiens. IV. Secondary vesicular yolk formation in frog oocytes.

Secondary yolk precursor complexes are differentiated from primary yolk precursor complexes in that little or no background matrix or small vesicles are present and that electron-dark, amorphous yolk protein fills the precursor at a very early stage of growth. Secondary precursors are formed in two ways; from multivesicular bodies or from the fusion of smooth-surfaced endocytotic vesicles. Ultimately, fusion of secondary precursors with multivesicular bodies makes them indistinguishable from primary precursors. Precursors are called yolk platelets when they are mainly crystalline with only a small amount of amorphous yolk protein present. The structure of the crystal is particulate with a spacing of 70--85 A. At high resolution, the particles are seen to measure approximately 20 X 60 A. The chemical composition and interpretations of studies of the crystal structure are discussed.     

Improved in vitro packaging of coliphage lambda DNA: a one-strain system free from endogenous phage

In previous systems for in vitro packaging of lambda DNA, phages are produced from the packaging components as well as from added DNA. We have developed a new genetic strategy for in vitro packaging that bypasses this endogenous phage problem. Our system employs a single bacterial strain whose lambda prophage codes for all of the packaging proteins but is deleted for cos, the packaging origin. Crude extracts of the single lysogen: (i) are virtually free from endogenous phages, (ii) package added lambda DNA efficiently and (iii) are easy to prepare. Using the cos- in vitro packaging system we show that packaging of lambda linear monomers is a second-order reaction, but that packaging from concatemers prepared by annealing or ligation is first order. We conclude that in our cos- system, linear monomers are a poor substrate for in vitro packaging but that packaging from concatemers works well.     

Isolation of Drosophila melanogaster Testes

The testes of Drosophila melanogaster provide an important model for the study of stem cell maintenance and differentiation, meiosis, and soma-germline interactions. Testes are typically isolated from adult males 0-3 days after eclosion from the pupal case. The testes of wild-type flies are easily distinguished from other tissues because they are yellow, but the testes of white mutant flies, a common genetic background for laboratory experiments are similar in both shape and color to the fly gut. Performing dissection on a glass microscope slide with a black background makes identifying the testes considerably easier. Testes are removed from the flies using dissecting needles. Compared to protocols that use forceps for testes dissection, our method is far quicker, allowing a well-practiced individual to dissect testes from 200-300 wild-type flies per hour, yielding 400-600 testes. Testes from white flies or from mutants that reduce testes size are harder to dissect and typically yield 200-400 testes per hour.     

Two new species of coccidia, Eimeria leucuri and E. oreoecetes (Protozoa: Eimeriidae), in grouse from Colorado.

Eimeria leucuri is described from white-tailed ptarmigan (Lagopus leucurus), and E. oreoecetes from white-tailed ptarmigan and blue grouse (Dendragapus obscurus) from Colorado. Oocysts of E. leucuri are ellipsoidal, 26.6 by 17.7 micron, each bearing a micropyle, micropyle cap, up to 4 polar granules, but no oocyst residuum. The lemon-shaped sporocysts are 15.4 by 6.7 micron, and have Stieda bodies and large amounts of sporocyst residuum. The sporocyst contents are enclosed in a membrane. Oocysts of E. oreoecetes are subspherical, 26.0 by 22.6 micron, and have up to 4 polar granules. The lemon-shaped sporocysts are 14.6 by 8.8 micron, and have both Stieda bodies and substiedal bodies and a large amount of sporocyst residuum. The sporocyst contents are enclosed in a membrane. These are the first coccidia to be described from these tetraonids.     

New and already known acanthocephalans mostly from mammals in Vietnam, with descriptions of two new genera and species in Archiacanthocephala

Adults of 2 new species and 2 new genera of acanthocephalans in class Archiacanthocephala, collected between 1998 and 2004 in Vietnam from the intestines of mammals, are described, i.e., Cucullanorhynchus constrictruncatus n. gen., n. sp. (Oligacanthorhynchidae) from a leopard Panthera pardus (Linnaeus) (Mammalia: Felidae) and Paraprosthenorchis ornatus n. gen. n. sp. (Oligacanthorhynchidae) from the Chinese pangolin Manis pentadactyla (Linnaeus) (Mammalia: Manidae). Adult Sphaerechinorhynchus macropisthospinus Amin, Wongsawad, Marayong, Saehoong, Suwattanacoupt, and Sey, 1998 (Plagiorhynchidae) are described for the first time from 2 females collected from a tiger Panthera tigris (Linnaeus) (Mammalia: Felidae) and from 1 male from a water monitor Varanus salvator Laurenti (Reptilia: Varanidae). Characteristic features distinguishing the new species or genera from related taxa are as follows. The trunk of C. constrictruncatus has an anterior hood in both sexes and a posterior constriction in females. The anterior trunk of P. ornatus has many small festoons and proboscis hooks are inserted in elevated papillae separated by beady, near hexagonal, ornate grids.     

Determination of adult stature from metatarsal length

The results of a study to determine the value of foot bones in reconstructing stature are presented. The data consist of length measurements taken on all ten metatarsals as well as on cadaver length from a sample of 130 adults of documented race, sex, stature, and, in most cases, age. Significant correlation coefficients (.58-.89) are shown between known stature and foot bone lengths. Simple and multiple regression equations computed from the length of each of these bones result in standard errors of estimated stature ranging from 40-76 mm. These errors are larger than those for stature calculated from complete long bones, but are approximately the same magnitude for stature calculated from metacarpals and fragmentary long bones. Given that metatarsals are more likely to be preserved unbroken than are long bones and given the ease with which they are accurately measured, the formulae presented here should prove useful in the study of historic and even prehistoric populations.     

Species of the genus Thrips from India (Thysanoptera)

Abstract. The species of Thrips Linnaeus from the Indian region are revised, and a key is provided to the thirty-three valid species, including eight new species and one new subspecies, Eight species customarily included in Taenio-thrips Amyot & Serville are here included in Thrips and six species are newly placed in synonymy: Thrips hawaiiensis (Morgan) (= Thrips exilicornis Hood from Africa); Thrips palmi Karny (= leucadophilus Priesner from Sudan); Thrips brunneus Anan. & Jaga. ( =speratus zur Strassen from South West Africa); Thrips tabaci Lind.(= kallarensis (Anan.) from India); Thrips sumatrensis Priesner (= lucaenae Moulton from Guam); Thrips simplex (Morison) (= Taeniothrips quinani Moulton from South Africa). Isoneurothrips Bagnall is regarded as a synonym of Thrips , and Isothrips is treated as a synonym rather than as a sub-genus. Two nominal species, beharensis (Ram. & Marg.) and rostratus (Ram. & Marg.) are considered unrecognizable at present.     

Characterization of the human cyclophilin gene and of related processed pseudogenes

The human cyclophilin gene was isolated from a genomic library derived from leucocyte DNA and sequenced. The gene contains five exons and four introns. The amino acid sequence deduced from the exons matches perfectly the one previously determined from the T-cell cyclophilin cDNA. A TATA box is visible in the promoter region and putative Sp1 binding sites are also found there as well as in the first intron. Six members of the middle repetitive Alu gene family are present in one or other orientation in the non-coding regions of the cyclophilin gene. Hybridisation of genomic DNA to probes derived from the promoter region or the first intron indicates that the cyclophilin gene is present as a single copy in the human haploid genome. Seven other cyclophilin-related DNA clones isolated from the same library were also characterized. They show a high degree of similarity to the cyclophilin cDNA and are colinear to it. However, multiple genetic lesions, often including deletion and/or insertion events which modify the reading frame, are found in these clones which are therefore likely to represent processed pseudogenes.