Gene Flow

No barriers to gene flow among sympatric polychromatic 'small' Telmatherina antoniae from Lake Matano, Indonesia

by Ryan Walter

Dispersal and population genetic structure of Telmatherina antoniae, an endemic freshwater Sailfin silverside from Sulawesi, Indonesia

by Ryan Walter

Coauthored with G Douglas Haffner and Daniel D Heath

Genetic structure and connectivity among lake populations of threatened Paratherina sailfin silversides from Sulawesi, Indonesia

by Ryan Walter

Coauthored with J. Derek Hogan, G. Douglas Haffner and Daniel D. Heath

A study of genetic differentiation and hybridization among oak species with divergent ecological and evolutionary profiles

by Charalambos Neophytou

Interfertile oaks in an island environment. II. Limited hybridization between Quercus alnifolia Poech and Q. coccifera L. in a mixed stand

by Charalambos Neophytou

Interfertile oaks in an island environment: I. High nuclear genetic differentiation and high degree of chloroplast DNA sharing between Q. alnifolia and Q. coccifera in …

by Charalambos Neophytou

Detecting interspecific and geographic differentiation patterns in two interfertile oak species (Quercus petraea (Matt.) Liebl. and Q. robur L.) using small …

by Charalambos Neophytou

Rediscovery of the “terrible hairy fly”, Mormotomyia hirsuta Austen (Diptera: Mormotomyiidae), in eastern Kenya, with notes on biology, natural history, and genetic variation of the Ukasi Hill population

by Warren Booth

Co-authored with: Robert S. Copeland, Ashley H. Kirk-Spriggs, Samuel Muteti, and Brian M. Wiegmann

Sixty-two years since last observed alive, Mormotomyia hirsuta Austen, the “terrible hairy fly”, was found inside and... more Sixty-two years since last observed alive, Mormotomyia hirsuta Austen, the “terrible hairy fly”, was found inside and outside a large, cave-like cleft boulder at the summit of Ukasi Hill in eastern Kenya, the type locality of the species. Adults were observed climbing the walls of the boulder and walking on thick layers of bat guano, in which larvae and puparia were also discovered. Large numbers of M. hirsuta were observed on and at the base of the northern side of the boulder, which at the time of capture experienced continuous shade during daylight hours. Only three individuals were observed at the southern opening, exposed to direct sunlight and hot, dry conditions. A collection of vertebrate bones and skulls from layers of guano both inside and outside the cleft revealed several vertebrate associates, including two species of Chiroptera, Chaerephon cf. bivittatus (Heuglin) and Tadarida aegyptiaca (E. Geoffroy), which are probably the two major guano-producing species responsible for the larval breeding medium. Male-biased sexual size dimorphism was pronounced in adult M. hirsuta, with seven body-part measurements, including legs, larger by 33–61 % in males than females. Males demonstrated isometric growth while female growth was allometric. In contrast to males, female head and thorax lengths did not increase proportionally with leg length. Estimates of genetic diversity in the Ukasi population show higher than expected allelic diversity and indicate possible gene flow and frequent population bottlenecks. To promote the conservation of this endangered species, a joint effort has been initiated between the International Centre of Insect Physiology and Ecology, Nairobi and the National Museums of Kenya, Nairobi, to gazette the Ukasi hill area as a protected site.

The full path of Janzen–Connell effects: genetic tracking of seeds to adult plant recruitment

by Pedro Jordano

Co-authored with Eugene W. Schupp. Molecular Ecology, 20, 3953–3955. 2011.

The Janzen–Connell (J-C) model (Janzen 1970; Connell 1971) has been a dominant yet controversial paradigm for forest... more The Janzen–Connell (J-C) model (Janzen 1970; Connell 1971) has been a dominant yet controversial paradigm for forest community dynamics for four decades, especially in the tropics. With increasing distance from the parent plant, the density of dispersed seeds decreases and, because of a reduced impact of distance- and density- responsive seed and seedling enemies, propagule survival increases, resulting in peak recruitment at some distance from the parent and little recruitment near adult conspecifics. This spacing generates gaps near adult trees for the recruitment of heterospecifics, enhancing species coexistence and species richness. Field studies, primarily focused on seeds and young seedlings, have repeatedly demonstrated increasing survival with increasing dis- tance from parents or decreasing density of propagules (e.g. Clark & Clark 1984; Gilbert et al. 1994; Swamy & Terborgh 2010). Yet a meta-analysis of distance-depen- dent propagule survival failed to support a general pat- tern of survival increasing with distance from adult conspecifics, suggesting that there is no need for further experimental tests of the J-C hypothesis in terms of diversity enhancement—results are species-specific, not general (Hyatt et al. 2003). However, a lack of consistent experimental results is not surprising. The outcome of tests of the hypothesis can vary as a function of many factors that can affect successive recruitment stages dif- ferently (Schupp 1992; Hyatt et al. 2003; Swamy & Ter- borgh 2010). This highlights a critical gap—a full test of the J-C model requires data demonstrating that effects carry over to recruitment of new reproductive adults, yet few studies have gone beyond early stages. There is strong inferential evidence that adult trees can show the imprint of J-C effects (e.g. Nathan et al. 2000; Howe & Miriti 2004), and focal individual modelling has clearly demonstrated that J-C effects can operate from sapling
through adult stages in a significant number of species (Peters 2003). It is likely that such results are not unusual, but there have been few attempts to demonstrate J-C spacing at the adult stage. In this issue of Molecular Ecology, Steinitz et al. (2011) studied the Mediterranean pine Pinus halepensis (Aleppo pine) and combined a unique situation with an innovative approach to provide the most elegant demonstration yet that adult recruits are spaced further from parents than expected from the ini- tial seed distribution, clear evidence of a J-C effect carry- ing over to reproductive adults. A major advancement of this study is that it incorporates estimates of the initial patterns of seed dispersal and parentage analysis of adult–offspring relationships, illustrating the value of combined field and genetic approaches.

Stynder, D. D., Ackermann, R. and Sealy, J. (2007). Craniofacial variation and population continuity during the South African Holocene. American Journal of Physical Anthropology 134: 489-500.

by Deano Stynder

We assess craniometric variation in 153 individually dated human crania from South Africa with the aim of... more We assess craniometric variation in 153 individually dated human crania from South Africa with the aim of investigating genetic continuity/discontinuity during the Holocene. Evidence from the archaeological record is used to pinpoint likely episodes of genetic discontinuity. Craniometric data are then used to assess the likelihood of genetic change having occurred. Two periods of possible genetic discontinuity are identified: i) c. 4,000 BP, when an increase in overall population size, shifts in site organization and diet, and reduced mobility, were accompanied by reductions in stature; ii) c. 2,000 BP, when the herding of domesticates and the use of pottery vessels were introduced into the region. Results indicate that there was a decrease in cranial size and concomitant size-related changes in craniofacial shape between c.4,000 BP and 3,000 BP. This was followed almost immediately by a recovery in craniofacial size and a return to pre-4,000 BP craniofacial shape at c. 3,000 BP. This recovery continued gradually, extending into the herder period without any major shifts in morphology at 2,000 BP. It is suggested that the fluctuations in craniofacial size/shape were related to changes in environmental factors. Results obtained are consistent with long term continuity in South African Later Stone Age populations during the Holocene.

DETECTION OF GENETIC STRUCTURE IN A BADGER POPULATION OF NORTH-EASTERN SPAIN (CATALONIA)

by Irene Del Cerro

Bosch M, Molina-Vacas G, Rodríguez-Teijeiro JD, Ferrando A
Submitted to European Journal of Wildlife Research

Cohesion, Gene Flow, and the Nature of Species

by Matt Barker

The empirical inadequacy of species cohesion by gene flow

by Matt Barker

Local Mobile Gene Pools Rapidly Cross Species Boundaries To Create Endemicity within Global Vibrio cholerae Populations.

by Otto X. Cordero Sanchez

Yan Boucher*, Otto X. Cordero, Alison Takemura, Dana E. Hunt, Klaus Schliep, Eric Bapteste, Philippe Lopez, Cheryl L. Tarrd, and Martin F. Polz
(2011) Mbio.

Vibrio cholerae represents both an environmental pathogen and a widely distributed microbial species comprised of... more Vibrio cholerae represents both an environmental pathogen and a widely distributed microbial species comprised of closely related strains occurring in the tropical to temperate coastal ocean across the globe (Colwell RR, Science 274:2025-2031, 1996; Griffith DC, Kelly-Hope LA, Miller MA, Am. J. Trop. Med. Hyg. 75:973-977, 2006; Reidl J, Klose KE, FEMS Microbiol. Rev. 26:125-139, 2002). However, although this implies dispersal and growth across diverse environmental conditions, how locally successful populations assemble from a possibly global gene pool, relatively unhindered by geographic boundaries, remains poorly understood. Here, we show that environmental Vibrio cholerae possesses two, largely distinct gene pools: one is vertically inherited and globally well mixed, and the other is local and rapidly transferred across species boundaries to generate an endemic population structure. While phylogeographic analysis of isolates collected from Bangladesh and the U.S. east coast suggested strong panmixis for protein-coding genes, there was geographic structure in integrons, which are the only genomic islands present in all strains of V. cholerae (Chun J, et al., Proc. Natl. Acad. Sci. U. S. A. 106:15442-15447, 2009) and are capable of acquiring and expressing mobile gene cassettes. Geographic differentiation in integrons arises from high gene turnover, with acquisition from a locally cooccurring sister species being up to twice as likely as exchange with conspecific but geographically distant V. cholerae populations. IMPORTANCE Functional predictions of integron genes show the predominance of secondary metabolism and cell surface modification, which is consistent with a role in competition and predation defense. We suggest that the integron gene pool's distinctness and tempo of sharing are adaptive in allowing rapid conversion of genomes to reflect local ecological constraints. Because the integron is frequently the main element differentiating clinical strains (Chun J, et al., Proc. Natl. Acad. Sci. U. S. A. 106:15442-15447, 2009) and its recombinogenic activity is directly stimulated by environmental stresses (Guerin E, et al., Science 324:1034, 2009), these observations are relevant for local emergence and subsequent dispersal.

Differential contribution of frugivores to complex seed dispersal patterns

by Pedro Jordano

co-authored with C. García, J. A. Godoy, and J. L. García-Castaño. Proceedings National Academy of Sciences USA, 104: 3278-3282. 2007.

Frugivores are highly variable in their contribution to fruit removal in plant populations. However, data are lacking... more Frugivores are highly variable in their contribution to fruit removal in plant populations. However, data are lacking on species-specific variation in two central aspects of seed dispersal, distance of dispersal and probability of dispersal among populations through long-distance transport. We used DNA-based genotyping techniques on Prunus mahaleb seeds dispersed by birds (small- and medium-sized passerines) and carnivorous mammals to infer each seed’s source tree, dispersal distance, and the probability of having originated from outside the study population. Small passerines dispersed most seeds short distances (50% dispersed <51 m from source trees) and into covered microhabitats. Mammals and medium-sized birds dispersed seeds long distances (50% of mammals dispersed seeds >495 m, and 50% of medium-sized birds dispersed seeds to >110 m) and mostly into open microhabitats. Thus, dispersal distance and microhabitat of seed deposition were linked through the contrasting behaviors of different frugivores. When the quantitative contribution to fruit removal was accounted for, mammals were responsible for introducing two-thirds of the immigrant seeds into the population, whereas birds accounted for one-third. Our results demonstrate that frugivores differ widely in their effects on seed-mediated gene flow. Despite highly diverse coteries of mutualistic frugivores dispersing seeds, critical long-distance dispersal events might rely on a small subset of large species. Population declines of these key frugivore species may seriously impair seed-mediated gene flow in fragmented landscapes by truncating the long-distance events and collapsing seed arrival to a restricted subset of available microsites.

Pollen, seeds, and genes: the movement ecology of plants

by Pedro Jordano

2010. . Heredity 105: 329-330. This is a comment on Richard Ennos' 1994 paper in Heredity: [Ennos RA (1994). Estimating the relative rates of pollen and seed migration among plant populations. Heredity 72: 250–259.]

Mating system and pollen flow between remnant populations of the endangered tropical tree, Guaiacum sanctum (Zygophyllaceae).

by Eric Fuchs

Co-authored with James L. Hamrick and published in Conservation Genetics.

Geographic contiguity, patterns of gene flow and genetic affinity among the tribes of Arunachal Pradesh.

by vasulu TS

Geographic contiguity, patterns of gene flow and genetic affinity among the tribes of Arunachal Pradesh.
S. Krithika, S. Maji and T.S. Vasulu. Intern J Hum Genet 2007,7(3):267-276.

Spatial Genetic Structure Within Size Classes of the Endangered Tropical Tree Guaiacum Sanctum (Zygophyllaceae)

by Eric Fuchs

Eric J. Fuchs and James L. Hamrick

Do’s and Don’ts of testing the geographic mosaic theory of coeveolution

by Devin Drown

The geographic mosaic theory of coevolution is stimulating much new research on interspecific interactions. We provide... more The geographic mosaic theory of coevolution is stimulating much new research on interspecific interactions. We provide a guide to the fundamental components of the theory, its processes and main predictions. Our primary objectives are to clarify misconceptions regarding the geographic mosaic theory of coevolution and to describe how empiricists can test the theory rigorously. In particular, we explain why confirming the three main predicted empirical patterns (spatial variation in traits mediating interactions among species, trait mismatching among interacting species and few species-level coevolved traits) does not provide unequivocal support for the theory. We suggest that strong empirical tests of the geographic mosaic theory of coevolution should focus on its underlying processes: coevolutionary hot and cold spots, selection mosaics and trait remixing. We describe these processes and discuss potential ways each can be tested.