Differential rates of phenotypic introgression are associated with male behavioral responses to multiple signals

Sexual selection on multiple signals may lead to differential rates of signal introgression across hybrid zones if some signals contribute to reproductive isolation but others facilitate gene flow. Competition among males is one powerful form of sexual selection, but male behavioral responses to multiple traits have not been considered in a system where traits have introgressed differentially. Using playbacks, mounts, and a reciprocal experimental design, we tested the hypothesis that male responses to song and plumage in two subspecies of red‐backed fairy‐wren (Malurus melanocephalus) explain patterns of differential signal introgression (song has not introgressed, whereas plumage color has introgressed asymmetrically). We found that males of both subspecies discriminated symmetrically between subspecies’ songs at a long range, but at a close range, we found that aggression was equal for both subspecies’ plumage and songs. Taken together, our results suggest that male behavioral responses hinder the introgression of song, but allow for the observed asymmetrical introgression of plumage. Our results highlight how behavioral responses are a key component of signal evolution when recently divergent taxa come together, and how differential responses to multiple signals may lead to differential signal introgression and novel trait combinations.     

Extending phylogeography to account for lineage fusion

Secondary contact between long isolated populations has several possible outcomes. These include the strengthening of preexisting reproductive isolating mechanisms via reinforcement, the emergence of a hybrid lineage that is distinct from its extant parental lineages and which occupies a spatially restricted zone between them, or complete merging of two populations such that parental lineages are no longer extant (“lineage fusion” herein). The latter scenario has rarely been explicitly considered in single‐species and comparative phylogeographic studies, yet it has the potential to impact inferences about population history and levels of congruence. In this paper, we explore the idea that insights into past lineage fusion may now be possible, owing to the advent of next‐generation sequencing. Using simulated DNA sequence haplotype datasets (i.e., loci with alleles comprised of a set of linked nucleotide polymorphisms), we examined basic requirements (number of loci and individuals sampled) for identifying cases when a present‐day panmictic population is the product of lineage fusion, using an exemplar statistical framework—approximate Bayesian computation. We found that with approximately 100 phased haplotype loci (each 400 bp long) and modest sample sizes of individuals (10 per population), lineage fusion can be detected under rather challenging scenarios. This included some scenarios where reticulation was fully contained within a Last Glacial Maximum timeframe, provided that mixing was symmetrical, ancestral gene pools were moderately to deeply diverged, and the lag time between the fusion event and gene pool sampling was relatively short. However, the more realistic case of asymmetrical mixing is not prohibitive if additional genetic data (e.g., 400 loci) are available. Notwithstanding some simplifying assumptions of our simulations and the knowledge gaps that remain about the circumstances under which lineage fusion is potentially detectable, we suggest that the recent release from data limitation allows phylogeographers to expand the scope of inferences about long‐term population history.     

Hematology and plasma chemistry values in free-ranging Humboldt penguins (Spheniscus humboldti) in Chile

To establish baseline hematologic and plasma biochemistry values in free-ranging Humboldt penguins (Spheniscus humboldti), heparinized blood samples were collected from 51 apparently healthy, adult Humboldt penguins residing at two colonies off the Chilean coast. Thirty samples were collected in April, 1992, from penguins inhabiting the Ex-islote de los Pájaros Niños in Algarrobo, Chile. In September, 1992, 21 samples were collected from birds inhabiting Isla de Cachagua, Chile. Hematologic values measured include packed cell volume, leucocyte count, leucocyte differential, and the presence of blood parasites. Plasma biochemistry values measured include glucose, blood urea nitrogen, creatinine, uric acid, calcium, inorganic phosphorous, sodium, potassium, chloride, total protein, albumin, globulin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total bilirubin, and creatine kinase. Only the mean values for chloride and for the number of eosinophils differed significantly between the two sample groups. No blood parasites were seen. © 1995 Wiley-Liss, Inc.     

Biocatalytic ketone reduction—a powerful tool for the production of chiral alcohols—part I: processes with isolated enzymes

Traditional cultivation-based methods to quantify microbial abundance are not suitable for analyses of microbial communities in environmental or medical samples, which consist mainly of uncultured microorganisms. Recently, different cultivation-independent quantification approaches have been developed to overcome this problem. Some of these techniques use specific fluorescence markers, for example ribosomal ribonucleic acid targeted oligonucleotide probes, to label the respective target organisms. Subsequently, the detected cells are visualized by fluorescence microscopy and are quantified by direct visual cell counting or by digital image analysis. This article provides an overview of these methods and some of their applications with emphasis on (semi-)automated image analysis solutions.     

披碱草与新麦草属间杂种的细胞遗传学研究

将澳大利亚披碱草(Elymus scabervar.scaber,2n=6x=42,StYW)和华山新麦草(Psathyrostachys huas-hanica,2n=2x=14,Ns)进行属间杂交,成功获得杂种F1。分析亲本及其杂种F1的形态特征、繁育特性及花粉母细胞减数分裂染色体配对行为发现:杂种F1形态特征介于父母本之间,分蘖数等农艺性状超过双亲;花粉完全不育,结实率为0。亲本减数分裂染色体配对正常,但杂种F1花粉母细胞在减数分裂中期I染色体几乎没有配对,其构型为:27.31Ⅰ 0.01Ⅱ(环) 0.32Ⅱ(棒) 0.01Ⅲ,C值仅为0.01。以上结果表明:澳大利亚披碱草的StYW染色体组与华山新麦草的Ns染色体组间无同源性,它们之间的亲缘关系甚远。     

Method for measuring substrate preferences by individual members of microbial consortia proposed for bioaugmentation

In this study we used the assimilation of isotope labeled CO(2) to measure the substrate preferences by two different bioaugmentation mixtures proposed for bioremediation of diesel oil contamination. All active microorganisms assimilate CO(2) in various carboxylation processes involved in growth. The CO(2) assimilation by the two mixtures was measured upon addition of glucose, diesel oil or specific compounds present in diesel oil (naphthalene, toluene, hexadecane, and octane). It was shown that within short term incubations with diesel oil (<5 h), one bioaugmentation mixture was superior to the other regarding the assimilation of CO(2). This observation was confirmed in a labor-intensive long term microcosm study (60 days). The applied method open various possibilities for fast pre-testing of substrate-preferences by microbial-bioaugmentation mixtures without microcosm experiments, onsite tests, and complicated chemical analysis. This study also demonstrates the possibility to obtain further information on the substrate preferences at a single cell level of phylogenetically defined microbial subgroups in bioaugmentation mixtures, based on combined analyses of microautoradiography and fluorescence in situ hybridization.     

Human-mediated introgression of exotic chukar (Alectoris chukar, Galliformes) genes from East Asia into native Mediterranean partridges

Mediterranean red-legged (Alectoris rufa) and rock (Alectoris graeca) partridge populations are affected by genetic pollution. The chukar partridge (Alectoris chukar), a species only partly native to Europe, is the most frequently introgressive taxon detected in the genome of hybrid partridges. Both theoretical (evolutionary) and practical (resources management) matters spur to get insight into the geographic origin of the A. chukar hybridizing swarm. The phenotypic A. rufa populations colonizing the easternmost part of the distribution range of this species, the islands of Elba (Italy) and Corsica (France), were investigated. The analysis of both mitochondrial (mtDNA: Cytochrome-b gene plus Control Region: 2,250 characters) and nuclear (Short Tandem Repeats, STR; Random Amplified Polymorphic DNA, RAPD) genomes of 25 wild (Elba) and 20 captive (Corsica) partridges, disclosed spread introgression of chukar origin also in these populations. All mtDNA haplotypes of Elba and Corsica partridges along with those we obtained from other A. rufa (total, n = 111: Italy, Spain, France) and A. graeca (n = 6, Italy), were compared with the mtDNA haplotypes of chukars (n = 205) sampled in 20 countries. It was found that the A. chukar genes detected in red-legged (n = 43) and rock partridges (n = 4) of Spain, France and Italy as well as in either introduced (Italy) or native (Greece, Turkey) chukars (n = 35) were all from East Asia. Hence, a well-defined geographic origin of the exotic chukar genes polluting the genome of native Mediterranean A. rufa and A. graeca (inter-specific level) as well as A. chukar (intra-specific level), was demonstrated.     

Transfer of small chromosome fragments of<Emphasis Type="Italic">Agropyron elongatum</Emphasis> to wheat chromosome via asymmetric somatic hybridization

The chromosome constitution of hybrids and chromatin patterns of Agropyron elongatum (Host)Neviski in F₅ somatic hybrid lines -1–3 and I-1-9 between Triticum aestivum L. and A. elongatum were analyzed. Based on the statistic data of pollen mother cells, F₅ I-1-9 and-1-3 had 20–21 bivalents with a frequency of 84.66% and 85.28%, of which, 89.83% and 89.57% were ring bivalents. The result indicated that both hybrid lines were basically stable in the chromosome constitution and behavior. RAPD analysis showed that the two hybrids contained biparental and integrated DNA. GISH (Genome in situ hybridization) revealed that in the form of small chromosome segments, A. elongatum chromatin was scattered on 4–6 wheat chromosomes near by the region of centromere and telomere in the two hybrid lines. SSR analysis indicated that A. elongatum DNA segments were distributed on the 2A, 5B, 6B and 2D wheat chromosomes in the hybrids, which was in accordance with the GISH results that small-segments intercalated poly-site.     

Characterization of serogroup C meningococci isolated from 14 provinces of China during 1966—2005 using comparative genomic hybridization

Neisseria meningitidis is a major cause of bacterial meningitis and septicemia worldwide. In China, serogroup A strains were responsible for over 95% of the cases, while serogroup B strains were mainly the cause of localized outbreaks and sporadic cases. Before 2003, serogroup C strains were only re-covered from a few sporadic cases. However, a sudden increase in the number of cases due to sero-group C strains occurred during 2003—2005 in Anhui Province, China. Many cases were found in other provinces at the same time. Multilocus sequence typing (MLST) results indicated that the unique se-quence type 4821 clone meningococci, a new hyper-virulent lineage, was responsible for the serogroup C meningitis outbreaks. We have completed the project of sequencing the whole genome of the Chi-nese N. meningitidis serogroup C representative isolate 053442. We fabricated a whole-genome mi-croarray of N. meningitidis isolate 053442 and analyzed the genome composition differences among 81 serogroup C isolates which were isolated from 14 provinces of China during 1966—2005. The com-parative genomic hybridization (CGH) result shows that the genome compositions of nearly all sero-group C isolates are similar to that of 053442. The products of many absent open reading frames (ORFs) are conserved hypothetical proteins. The results will provide a valuable resource from which one can analyze the genome composition and genetic background of serogroup C meningococci in China.     

Cloning genes from a library using a clustering strategy and PCR

A new polymerase chain reaction (PCR)-based method is described for the isolation of clones of interest from a library when only part of a sequence is available. In actuality, this occurs with many genomes that have been partially sequenced using a random strategy. The method presented here, discriminating clusters by PCR (DCbyPCR), is a nonradioactive and improved alternative to colony hybridization.