Pollination genetics of hybridization in sympatric populations of asclepias exaltata and a. syriaca (asclepiadaceae)

Enzyme electrophoresis of pollinia and seeds was used to identify pollinia on pollinators, interspecific pollinations, and hybrid seed production in sympatric populations of Asclepias exaltata and A. syriaca. The frequency of mixed pollinia loads on pollinators was low. Only 4.1% (N= 169 pollinia) and 8% (N= 244 pollinia) of the pollinia collected from pollinators of A. syriaca and A. exaltata, respectively, were identified as pollinia from the other species. Natural levels of interspecific pollination, 3.6% (N = 166 pollinia) on A. syriaca and 3.1% (N = 228 pollinia) on A. exaltata, were typically lower than the number of foreign pollinia carried by pollinators. Hybrid seeds were identified in only two of 208 A. syriaca fruits and one of 178 A. exaltata fruits. Hybrid seeds were largely underdeveloped in the single A. exaltata fruit. High fruit set (34.7%) and near normal seed set following hand-pollination of A. syriaca with A. exaltata pollinia suggest that hybridization is more likely between these taxa when A. syriaca is the maternal parent. Our findings indicate that the likelihood of hybridization between A. exaltata and A. syriaca is remote. Nevertheless, introgressive hybridization has been documented in these species, which suggests that hybridization remains a strong evolutionary force even for species that infrequently interbreed.     

Isolation and characterization of microsatellites in Leuciscus cephalus (Cypriniformes,Cyprinidae) and cross‐species amplification within the family Cyprinidae

Thirteen polymorphic microsatellites were isolated from Leuciscus cephalus, a widespread cyprinid species with great ecological tolerance. Together with the cross‐species amplification of six additional loci originally published for three cyprinid fish species, we optimized a multiplex panel for L. cephalus allowing the genotyping of 19 polymorphic loci. Number of alleles and heterozygosity per locus in a sample of 20 fish individuals ranged from two to 16 and from 0.05 to 0.90, respectively. These primers will be useful in determining the population structure of L. cephalus. In addition, successful cross‐amplification was obtained for several species of Cyprinidae.     

Fifteen polymorphic microsatellite loci from Jamaican streamertail hummingbirds (Trochilus)

We isolated and characterized 15 microsatellite loci from the endemic Jamaican streamertail hummingbird Trochilus polytmus. Loci were screened in 12 individuals of both T. polytmus and its sister species T. scitulus, also a Jamaican endemic. The number of alleles per locus ranged from 2 to 10, observed heterozygosity ranged from 0 to 1, and the probability of identity values ranged from 0.038 to 0.663. These new loci provide tools for characterizing the narrow hybrid zone between the two species.     

Characterization of microsatellite loci in two closely related Lissotriton newt species

We have developed eight di- and tetranucleotide Lissotriton microsatellite markers. Eight loci were polymorphic in the palmate newt Lissotriton helveticus and six were polymorphic in the smooth newt L. vulgaris. Polymorphism detected in 33 and 37 individuals per species ranged from 3 to 15 alleles. These markers are suitable for the investigation of population structure, genetic variation and taxonomic identification in the two focal species, and may also be of use in other Lissotriton–Triturus species.     

Fifteen polymorphic simple sequence repeat markers from expressed sequence tags of Liriodendron tulipifera

We developed and evaluated simple sequence repeat (SSR) markers derived from expressed sequence tags (ESTs) of Liriodendron tulipifera. Characteristics of 15 EST‐SSR loci were investigated using 33 L. tulipifera individuals. The number of alleles per locus ranged from two to five. The expected and observed heterozygosities ranged from 0.216 to 0.751 and from 0.182 to 0.97, respectively. These loci were further tested for their cross‐species transferability to Liriodendron Chinense. Because of their high level of polymorphism and transferability, our 15 single‐locus EST‐SSR markers will be valuable tools for research on mating system, population genetics and systemic evolution of Liriodendron.     

Characterization of microsatellite DNA markers in the Emei moustache toads (<Emphasis Type="Italic">Leptobrachium boringii</Emphasis>)

We report ten microsatellite loci in the Emei moustache toads, Leptobrachium boringii. Markers were obtained by screening a genomic library enriched for microsatellite motifs. Twenty-four individuals from one breeding site were examined and ten loci were polymorphic. The number of alleles per locus ranged from 3–9 with an average of 6.3/locus. The expected heterozygosity and observed heterozygosity ranged from 0.3874 to 0.8432, and from 0.4583 to 0.9167, respectively. Cross-species amplification was tested in a closely related species L. leishanensis. These markers will be useful in future studies on characterizing the mating system of the species.     

A panel of polymorphic EST-derived microsatellite loci for the small yellow croaker (Larimichthys polyactis)

Small yellow croaker (Larimichthys polyactis) is an important economic species of marine fishery. We developed and evaluated simple sequence repeat (SSR) markers from expressed sequence tags (ESTs) of Pseudosciaena crocea, Paralichthys olivaceus and Psetta maxima. Characteristics of nine EST–SSR loci were investigated using 46 L. polyactis individuals. The number of alleles per locus ranged from 2 to 6. The observed heterozygosity ranged from 0.0652 to 0.7391, while the expected heterozygosity ranged from 0.0638 to 0.7754. Seven loci departed from Hardy–Weinberg equilibrium (P < 0.01) significantly. These loci and markers will be useful for population genetics and systemic evolution among species of small yellow croaker.     

Oviposition preference and larval performance of monarch butterflies (Danaus plexippus) on two invasive swallow-wort species

The potential of two invasive herbaceous vines Vincetoxicum nigrum (L.) Moench and Vincetoxicum rossicum (Kleopow) Barbar. (Asclepiadaceae) to reduce monarch butterfly (Danaus plexippus L.) (Lepidoptera: Nymphalidae, Danainae) populations was investigated by evaluating oviposition selection in adult monarch butterflies and larval feeding preference in choice tests comparing the native host plant of monarch butterflies, Asclepias syriaca L. (Asclepiadaceae) and the two non‐indigenous Vincetoxicum species. In both choice and no‐choice tests, no eggs were oviposited on either of the two Vincetoxicum species whereas over 66 eggs per female were oviposited on A. syriaca plants. All first instar larvae allowed to feed on A. syriaca for 48 h survived while a significantly lower proportion survived on V. rossicum (44%) and V. nigrum (14%). Mean weight of larvae that did survive on the Vincetoxicum species was significantly lower than the mean weight of larvae that fed on A. syriaca. The mean weight of surviving larvae, however, did not differ between the two Vincetoxicum species. The mean proportion of leaves consumed by larvae feeding on A. syriaca was significantly greater than the mean proportion of leaves consumed by larvae feeding on either Vincetoxicum species. Findings from this research indicate that V. rossicum and V. nigrum are not viable hosts of monarch butterflies and are likely to pose little direct threat to their populations as oviposition sinks. The ability of these highly aggressive plants, however, to out‐compete and displace the native host of monarchs, A. syriaca, may pose a more serious threat. The potential of monarch populations to adapt to the two Vincetoxicum species as host plants over the long‐term is discussed.     

Development of twelve polymorphic microsatellite loci in polyploid endangered Omphalogramma vincaeflora Franch. (Primulaceae)

A total of twelve polymorphic microsatellite loci were developed from polyploid endangered species, Omphalogramma vincaeflora (Primulaceae). These loci were screened for variability among 45 individuals from three populations in China. The primers amplified loci with allele number ranging from 3 to 9, with an average of 4.25 per locus. Polymorphism information content ranged from 0.23 to 0.86. Nei’s genetic diversity ranged from 0.34 to 0.86. These primers provide an opportunity to use polymorphic DNA markers to study the population genetic structure and its breeding system in this species.     

Polymorphic microsatellite markers for the Iberian rock lizard species,Iberolacerta cyreni,and cross‐species priming in other Iberolacerta species

Eight polymorphic microsatellite loci are described for the Iberian rock lizard species, Iberolacerta cyreni. Loci were isolated from a partial genomic library that had been enriched for AAAG repeat sequence. Number of alleles per locus ranged from two to 13 in a sample of 24 individuals from the Sierra de Guadarrama (central Spain). Observed heterozygosity ranged from 0.13 to 0.96. At least three loci were amplified and polymorphic in four other Iberian rock lizard species: Iberolacerta monticola, Iberolacerta bonnali, Iberolacerta aranica and Iberolacerta aurelioi. These markers will be used to study mating strategies and reproductive success in I. cyreni.     

Isolation and characterization of microsatellites in Sparganium emersum and cross‐species amplification in the related species S. erectum

We developed seven novel polymorphic microsatellite loci for the aquatic macrophyte Sparganium emersum (Sparganiaceae). These were characterized on 62 individuals collected from nine different populations. In this set of individuals, seven to 20 alleles per locus were detected and observed heterozygosity ranged between 0.16 and 0.95. Cross‐species amplification was tested in the related species Sparganium erectum, and was successful for five of the seven microsatellite loci.     

Isolation and characterization of microsatellite loci in Lesquerella fendleri (Brassicaceae) and cross‐species amplification

Fifteen novel microsatellite primer pairs are presented for Lesquerella fendleri, which were developed from seven dinucleotide, five trinucleotide and three tetranucleotide microsatellite DNA loci. These loci were characterized for 40 individuals from 24 localities throughout the species range. The number of alleles observed per locus ranged from three to 16, the observed heterozygosity ranged from 0.175 to 0.750, and the polymorphic information content ranged from 0.218 to 0.889. Cross‐species transferability tested on nine species of Lesquerella and one species of the related genus Physaria indicates that these primer pairs may be useful for population genetic studies of other species in Lesquerella and possibly other closely related genera.     

Isolation and characterization of eight dinucleotide microsatellite loci from two closely related clupeid species (Alosa alosa and A. fallax)

Eight dinucleotide microsatellite loci were developed through an enrichment protocol for allis shad (Alosa alosa) and twaite shad (A. fallax). Cross‐species amplification was successful for all loci isolated. The number of alleles per locus ranged from three to nine for A. alosa and from two to seven for A. fallax, while the observed heterozygosity ranged from 0.267 to 0.926 and from 0.240 to 0.727, respectively. These markers will constitute useful tools for studies of population structure and gene flow between two closely related hybridizing species.     

Characterization,multiplex conditions,and cross‐species utility of tetranucleotide microsatellite loci for Blanchard's cricket frog (Acris crepitans blanchardi)

We have isolated and characterized 17 tetranucleotide microsatellite loci for Blanchard's cricket frog (Acris crepitans blanchardi), an anuran common in the central USA. Sixteen loci were organized into four multiplex amplification reactions. These loci were highly polymorphic when screened in 55 individuals from two distant populations, with 11–48 alleles per locus (average = 24.8). Observed and expected heterozygosities ranged from 0.18 to 0.97 and from 0.17 to 0.96, respectively. Nine loci were also polymorphic in Acris crepitans crepitans, with seven polymorphic in Acris gryllus. Five loci amplified in all three taxa. These loci will be useful for population‐ and species‐level investigations of this widespread group.     

Isolation of polymorphic microsatellite loci in Hemerocallis fulva and Hemerocallis citrina (Hemerocallidaceae)

Twenty microsatellite loci were isolated from a hybrid of two daylilies, Hemerocallis fulva and Hemerocallis citrina. We characterized individuals from two H. fulva populations and two H. citrina populations in Japan and observed three to 20 alleles per locus in H. fulva and one to 19 alleles per locus in H. citrina. Mean observed heterozygosity within populations ranged from 0.35 to 0.85 in H. fulva and from 0 to 0.95 in H. citrina. In about a half of the loci, the observed heterozygosity did not deviate from Hardy–Weinberg equilibrium. These loci are proved useful in studying gene flow and qualitative trait loci mapping using the two species.     

Development and characterization of microsatellite markers for the endangered northern riffleshell mussel Epioblasma torulosa rangiana (Bivalvia: Unionidae)

Primers for six polymorphic microsatellite loci were developed for the endangered northern riffleshell Epioblasma torulosa rangiana from the Sydenham River, Ontario, Canada. These loci along with an additional nine microsatellite loci, developed from other unionoid species, available in the literature, were tested and characterized on individuals from two populations in the Allegheny River; one population in French Creek, PA, USA, and one population from the Sydenham River. Allelic diversity ranged from two to 28 alleles per locus and averaged 13.7 per locus. These primers are being used in a rangewide study on the conservation genetics of remaining extant populations of the northern riffleshell.     

Development and characterization of nineteen polymorphic microsatellite loci from seaside alder, Alnus maritima

We isolated and characterized 19 microsatellite loci from the endangered seaside alder, Alnus maritima. Loci were screened in 24 individuals of A. maritima and four individuals of its congener the hazel alder, A. serrulata. The number of alleles per locus ranged from 2 to 6, observed heterozygosity ranged from 0 to 0.952, and the probability of identity values ranged from 0.126 to 0.850. These new loci provide tools for characterizing the population genetics of this rare tree.     

Development and characterization of microsatellite markers in Abies firma and interspecific amplification in other Japanese Abies species

Abies firma is a dominant coniferous tree species endemic to Japan. We isolated eight microsatellite loci from needles of this tree species and tested their polymorphism among 26 A. firma individuals. Six of them showed polymorphism, with two to 16 alleles per locus. Their expected heterozygosities ranged from 0.075 to 0.922. Moreover, interspecific amplification among Abies sachalinensis, Abies mariesii and Abies veitchii was successful in majority of the isolated loci, suggesting that these loci may be useful for characterization of other fir species.     

Development of microsatellite markers for the endangered freshwater pearl mussel Margaritifera margaritifera L. (Bivalvia: Unionoidea)

Freshwater pearl mussels (Margaritifera margaritifera L.) are among the most critically endangered freshwater invertebrates. We describe the isolation and characterization of the first microsatellite markers for this species, which were obtained by screening 4900 recombinant clones from two genomic libraries. Thirteen loci revealed polymorphisms as demonstrated on 42 tested individuals from four river drainages. Allelic richness ranged from two to 12 alleles and averaged 6.8 alleles per locus with heterozygosity levels varying from 0 to 0.850 for observed heterozygosity (H_O) and from 0.174 to 0.850 for expected heterozygosity (H_E). Deficiency of heterozygous genotypes was observed in eight of 13 loci.     

Eight microsatellite loci in Phaedranassa schizantha Baker (Amaryllidaceae) and cross-amplification in other Phaedranassa species

Phaedranassa schizantha is a species endemic to Ecuador from which eight polymorphic microsatellite loci were isolated from an enriched genomic library. A total of 31 alleles with an average of four alleles per locus were detected across 29 individuals from a single natural population of P. schizantha. Observed heterozygosity ranged from 0.05 to 0.68. Most of the eight loci were successfully amplified in six Phaedranassa species. Five of those species are either “Vulnerable” or “Endangered” under IUCN criteria. These loci will be used to investigate patterns of inter- and intraspecific variation of Phaedranassa species, which will contribute data relevant to their conservation status.