摘要:

AbstractEight highly variable microsatellite loci were used to examine the genetic variability and differentiation of grey seals (Halichoerus grypus) at two widely spaced British breeding colonies. Samples were collected from adults and pups on the island of North Rona, off the north‐west coast of Scotland, and on the Isle of May, situated at the mouth of the Firth of Forth on the east coast Highly significant differences in allele frequencies between these two sites were found for all eight loci, indicating considerable genetic differentiation. Thus, although grey seals are known to range over very large areas outside the breeding season, site fidelity of adults and philopatry of pups for these breeding colonies must be sufficiently common to have effects, through genetic drift, at the sub‐population level. Migration rate was estimated using Wrighf's fixation index (FST), Slatkin's private alleles model and the new statistic,RST, which is analogous to (FST) but which takes into account the process of microsatellite mutation. An almost 8‐fold discrepancy between the values we obtained provides cautionary evidence that microsatellite loci may contravene one or more of the assumptions on which these methods are

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1995.tb00266.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe decline of native Hawaiian forest birds since European contact is attributed to factors ranging from habitat destruction to interactions with introduced species. Remaining populations of Hawaiian honeycreepers (Fringillidae: Drepanidinae) are most abundant and diverse in high elevation refuges above the normal range of disease‐carrying mosquitoes. Challenge experiments suggest that honeycreepers are highly susceptible to avian malaria (Plasmodiumsp.) but resistance exists in some species. In order to detect low levels of malarial infection and quantify prevalence ofPlasmodiumin high elevation natural populations of Hawaiian birds, a polymerase chain reaction (PCR) based diagnostic test was developed that identifies rRNA genes ofPlasmodiumin avian blood samples. Quantitative competitive PCR (QC‐PCR) experiments indicate that the detection limit of our test is an order of magnitude greater than that reported for human malaria DNA blot tests. Compared with standard histological methods, the PCR test detected a higher prevalence of diseased birds at mid‐elevations. Malaria was detected in three species of native birds living in a high elevation wildlife refuge on the island of Hawaii and in four species from Maui. Our results show that avian malaria is more widespread in Hawaiian forests than previously thought, a finding that has important conservation implications for these threatened sp

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1995.tb00267.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractGeneric variation within and among one Finnish and three Swedish populations ofFomitopsis pinicola(Schwarts: Fr.) Karst. were studied by amplifying DNA from hap‐loid isolates originating from single spore cultures using two arbitrary primers. Analysis offspring from single fruit bodies revealed only three pairs of codominant alleles among 42 variable genetic markers, the remaining 38 segregated independently. Genetic similarity was measured in terms of Euclidean distance. Individuals in the Finnish population tended to form a distinct cluster in the principal component analysis. Variation within and among populations/regions was partitioned by Analysis of Molecular Variance — AMOVA. Within population variation accounted for 91.6% of the total genetic variation. The remaining 7.68% was accounted for by variation between the Finnish population and each of the three Swedish ones. Variation among the Swedish populations accounted for only 0.72% of the total variation. Wright'sFstwas 0.17 for all four populations and 0.13 for the three Swedish populations. These relatively low values indicate that there is gene flow among all populations or that they are derived from a common ancestral population. The observed pattern of genetic variation is probably the result of effective spore dispersal and the continuous distribution of this common early successional spec

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1995.tb00268.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractForty‐nine populations of brook charr (Salvelinus fontinalis) from Algonquin Park lakes and rivers were analysed for mitochondrial DNA variation. Haplotypic distributions of wild fish in the Algonquin Park region of Ontario, Canada, predominantly reflect postglacial dispersal patterns into the region in spite of substantial hatchery plantings. Two major refugial groupings colonized this region. Northern and eastern watersheds (Amable du Fond, Bonnechere, and northern Petawawa), were colonized primarily by haplotype 1 fish (B1 phylogenetic assemblage), while Oxtongue River, southern Petawawa, and York River populations were colonized predominately by fish from the B2 and A mtDNA phylogenetic assemblages. Fish with haplotypes in the A and B2 phylogenetic assemblages are common in the Lake Huron drainage. All watersheds in the Park drain into the Ottawa River, except the Oxtongue drainage (part of the Lake Huron watershed). This suggests that early glacial outflows south of the Algonquin Park region (Kirkfield‐Trent) may have been colonized by fish that initially invaded ‘Ontario island’ (south‐western Ontario), while fish which invaded northern Algonquin Park were derived from a different refugial grouping(s) which may have involved colonization both up the Ottawa River drainage, and/or from a more westerly (Mississippian) refugial grouping. A majority of the populations in Algonquin Park have been planted with hatchery reared brook charr since the 1940s. The Hills Lake or ‘Domestic’ strain was used almost exclusively for these plantings. Comparisons of mtDNA haplotypic distributions in hatchery and wild fish suggests that hatchery females had minimal spawning success and/or their progeny had poor survivorshi

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1995.tb00269.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe Australian sheep blowfly,Lucilia cuprina, was first identified in New Zealand in 1988 and is now found to have spread throughout many sheep‐farming regions.L. cuprinais estimated to have been present in New Zealand100 years. The aim of this study was to determine the genetic effects of colonization ofL. cuprinaand to compare populations ofL. cuprinafrom these two countries in terms of genetic variability and differentiation. Allozyme electrophoresis was used which revealed variability at six loci. 1680 blowflies were examined from 56 sites throughoutL. cuprina'srange in both countries. Genetic variability at each locus in terms of allele composition was found to be high and genetic differentiation varied considerably in New Zealand in comparison to Australia. Temporal sampling in New Zealand suggests seasonal fluctuations of population size in the recently colonized region of the South Islan

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1995.tb00270.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe slow rate of mtDNA evolution in turtles poses a limitation on the levels of intraspecific variation detectable by conventional restriction fragment surveys. We examined mtDNA variation in the gopher tortoise (Gopherus polyphemus) using an alternative restriction assay, one in which PCR‐amplified segments of the mitochondrial genome were digested with tetranucleotide‐site endonucleases. Restriction fragment polymorphisms representing four amplified regions were analysed to evaluate population genetic structure among 112 tortoises throughout the species' range. Thirty‐six haplotypes were identified, and three major geographical assemblages (Eastern, Western, and Mid‐Florida) were resolved by UPGMA and parsimony analyses. Eastern and Western assemblages abut near the Apalachicola drainage, whereas the Mid‐Florida assemblage appears restricted to the Brooksville Ridge. The Eastern/Western assemblage boundary is remarkably congruent with phylogeographic profiles for eight additional species from the southeastern U.S., representing both freshwater and terrestri

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1995.tb00271.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractGenes of the major histocompatibility complex (Mhc) are the most polymorphic functional loci in mammalian populations, but little is known ofMhcvariability in natural populations of nonmammalian vertebrates. To help extend such studies to birds and relatives, we present a pair of degenerate primers that amplify polymorphic segments of one chain (the β chain) of the class II genes from the major histocompatibility complex (Mhc) of archosaurs (birds + crocodilians). The primers target two conserved regions lying within portions of the antigen‐binding site (ABS) encoded by the second exon and amplify multiple genes from both genomic DNA and cDNA. The pattern of nucleotide substitution in ABS codons of 51 sequences amplified and cloned from five species of passerine birds and an alligator (Alligator mississippiensis) indicates that archosaurian class II β genes are subject to selective forces similar to those operating in mammalian populations. Hybridization of a genomic clone generated by the primers revealed highly polymorphic bands in a sample of Florida scrub jays (Aphelocoma coerulescens coerulescens). Because the primers amplify only part of the ABS from multiple class II genes, they will be useful primarily for generating species specific clones, thereby providing a critical inroad to more detailed structural and evolutionary stud

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1995.tb00272.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractPostglacial migration is a major factor responsible for the patterns of genetic variation we see in natural populations. Fossil pollen data indicate that early postglacial colonists such as oak, were able to take both western and eastern migration routes into Britain. Analysis at a finer level is now permitted by the use of modern molecular techniques. A 13‐bp duplication in the chloroplast tRNALeulintron occurs in natural populations of East Anglian oaks, but is not found in other parts of Britain or from mainland Europe. The distribution of this marker suggests that the mutation occurred either in southern England, or during migration from the mainland, and became fixed in a source population from which East Anglia was colonized. Planting of non‐native trees for roadside boundaries and in the grounds of old houses and estates, explains the absence of the marker from some East Anglian o

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1995.tb00273.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractWe report an attempt to induce extrapair copulations and fertilizations in a species with a low intensity of sperm competition, the pied flycatcherFicedula hypoleuca.Shortly after pair formation males were made less attractive to females by removing certain wing and tail feathers. Earlier research has shown that this manipulation reduces a male's pairing success. The idea was to test whether females mated to such males (N= 9) were more likely to obtain extrapair fertilizations than females mated to unmanipulated controls (N= 9). Paternity testing was carried out on all 98 young in the 18 broods, using a set of six microsatellite markers isolated from the species. Extrapair fertilizations were revealed in only three (17%) broods; two broods of handicapped males and one of a control male. A total of seven (7%) offspring were not genetically related to their putative father, a level which agrees well with results of other studies of this and other populations. We conclude that there was no evidence to suggest that the fertilization pattern was altered by the experimental manipulation. One reason for the lack of response could be that female mate choice in this species is based on male phenotypic, and not genotypic, quality.

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1995.tb00274.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractTwo sections of the control region and the genes coding for NADH dehydrogenase sub‐units 5 and 6 (ND‐5/6) of mitochondrial DNA (mtDNA) were amplified fromPhoxinus eoswith the polymerase chain reaction. Both sections of the control region were sequenced directly while the ND‐5/6 fragment was sequenced in from each end only. Additionally, the entire ND‐5/6 fragment was examined for sequence variation using RFLP analysis. No sequence variation was detected in the control region among 70 individuals sampled from 18 populations across three Ontario regions (Spanish River, Madawaska R. and Cataraqui R.). To examine ND‐5/6 variation, a total of 75 individuals were sampled from five populations representing two of the three regions (Madawaska River and Cataraqui R.). Six haplotypes were detected by direct sequencing and four by RFLP analysis. Estimates of population subdivision from RFLP data, sequence analysis, and the two data sets combined for the ND‐5/6 fragment, suggest that gene flow is restricted within and between regions. However, estimates of sequence divergence for both sequence and RFLP analysis of this fragment suggested that populations were either founded by already differentiated populations or that populations were founded by a single stock and divergence between regions occurred prior to isolation of populations within regions. These estimates of population structure are much greater than those obtained from allozyme analysis. Additionally, high levels of heterozygosity in nuclear DNA, but low mtDNA diversity suggests that populations have experienced reductions in population size sufficient to reduce only mtDNA variation. Random lineage extinction and limited time for the accumulation of new mutations are likely responsible for low levels of mtDNA variation in ND‐5/6 and the control region, while functional constraints may limit variation more than expected in the control region in dace and

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1995.tb00275.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY