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Strong phylogeographic relationships among three goat breeds from the Canary Islands.

We partially sequenced the mitochondrial D-loop region in 47 individuals from eleven Spanish and foreign goat breeds. Phylogenetic analysis of these sequences allowed us to identify a particular D-loop haplotype shared by individuals from the Palmera, Majorera and Tinerfeña Canarian breeds. Genotyping of 281 goats from 17 different breeds by PCR-Hpall RFLP evidenced that the geographical distribution of this haplotype is restricted to the Canary Islands. This ancestral mitochondrial haplotype might originate in the domestic goat herds brought by the native Canarian inhabitants approximately 3000 years ago. Although we observed other miscellaneous D-loop haplotypes in the Palmera, Majorera and Tinerfeña breeds, any of them allowed us to group individuals from these three populations in a single cluster, a feature that suggests that these haplotypes might have diverse origins. The remarkable degree of phylogeographic structure of the Canary goat breeds with regard to other Spanish and foreign populations might be attributed to the isolation of these breeds in the Canary Islands for approximately 2500 years, without exposure to the migratory movements and commercial trading events that probably affected the genesis of most domestic goat breeds worldwide. The Canarian D-loop haplotype can be efficiently genotyped by using DNA isolated from milk and cheese samples, which paves the way for the future establishment of a Canary breed identity test for these dairy products.

Animals↗

Comparative phylogeography across two trophic levels: the oak gall wasp Andricus kollari and its chalcid parasitoid Megastigmus stigmatizans.

Insect parasitoids are important components of many terrestrial ecosystems. However, relatively little is known about the mechanisms responsible for structuring their populations. Here we investigate the ability of Megastigmus stigmatizans, an oak gall wasp parasitoid, to track its host Andricus kollari over two different timescales, and examine its current population structure across a divide in host population structure. The divide represents a transition in gall wasp host-plant species and offers the opportunity to examine whether the split, which divides gall wasp populations, manifests itself in the next trophic level. Analysis of mitochondrial haplotype data for parasitoid and host reveals: (i) A similar phylogeographic population structure for both, with Iberian populations more derived with respect to more eastern populations. (ii) It is likely that the host colonized the Iberian refuge earlier than the parasitoid, probably by at least one glacial cycle. (iii) Recent range expansion of central European host populations northwards has resulted in pursuit by parasitoids from the same geographic origin. (iv) In addition, Iberian parasitoid populations have crossed a major divide in host population structure to invade northern Europe. Such human-facilitated escape from natural refugial distributions may have important implications for the composition and structure of northern European gall wasp communities.

Animals↗

Potential refugia in Taiwan revealed by the phylogeographical study of Castanopsis carlesii Hayata (Fagaceae).

In this study, we examined spatial patterns of chloroplast DNA (cpDNA) variation in a total of 30 populations of Castanopsis carlesii Hayata (Fagaceae), a subtropical and temperate tree species, including 201 individuals sampled throughout Taiwan. By sequencing two cpDNA fragments using universal primers (the trnL intron and the trnV-trnM intergenic spacer), we found a total of 1663 bp and 21 polymorphic sites. These gave rise to a total of 28 cpDNA haplotypes. The level of differentiation among the populations studied was relatively high (GST = 0.723). Two ancestral haplotypes are widely distributed. The Central Mountain Ridge (CMR) of Taiwan represents an insurmountable barrier to the east-west gene flow of C. carlesii. Among the populations studied, three separated populations, at Lienhuachih, Fushan and Lichia, have high nucleotide diversity. Estimates of NST-GST for populations on both sides of the CMR indicate that no phylogeographical structure exists. According to the genealogical tree, number of rare haplotype and population genetic divergence, this study suggests that two potential refugia existed during the last glaciation: the first refugium was located in a region to the north of Hsuehshan Range (HR) and west of the CMR; the second refugium was located in south, especially southeastern Taiwan. In fact, the second refugium happens to be the same as that reported for Quercus glauca. A 'star-like' genealogy is characteristic when all haplotypes rapidly coalesce and is a general outcome of population expansion. The neutrality test and mismatch distribution also suggest demographic expansion recovering from a bottleneck.

Base Sequence↗

Estrogen receptor beta (ESR2) polymorphisms in interaction with estrogen receptor alpha (ESR1) and insulin-like growth factor I (IGF1) variants influence the risk of fracture in postmenopausal women.

UNLABELLED: In this large population-based cohort study, variants in ESR2 were associated with increased risk of vertebral and incident fragility fracture in postmenopausal women. Interaction of ESR2 with ESR1 and IGF1 was determined and revealed a deleterious genetic combination that enhances the risk of osteoporotic fracture. INTRODUCTION: Osteoporosis is a complex disease with strong genetic influence, but the genes involved are ill-defined. We examined estrogen receptor beta (ESR2) polymorphisms in interaction with estrogen receptor alpha (ESR1) and insulin-like growth factor I (IGF1) variants in relation to the risk of osteoporotic fracture, BMD, and bone geometry. MATERIALS AND METHODS: In the Rotterdam study, a prospective population-based cohort of elderly white individuals, we studied six single nucleotide polymorphisms (SNPs) in ESR2 (n = 6343, 60% women). We analyzed the genetic variants in the form of haplotypes reconstructed by a statistical method. Results refer to the most frequent ESR2 haplotype 1 estimated from two SNPs in intron 2 and the 3'-untranslated region (UTR). Outcomes included vertebral and incident nonvertebral fractures, BMD, and hip structural analysis (HSA). We also studied the interaction with (the most frequent) ESR1 haplotype 1 estimated from the PvuII and XbaI polymorphisms and an IGF1 promoter CA-repeat. RESULTS: Compared with ESR2 haplotype 1 noncarriers, female homozygous carriers had a 1.8- and 1.4-fold increased risk of vertebral and fragility fractures. HSA showed that ESR2 haplotype 1 homozygote women had 2.6% thinner cortices, 1.0% increased neck width, and 4.3% higher bone instability (buckling ratios). For testing the gene interaction, we assumed a recessive model of ESR2 haplotype 1. Female homozygous carriers of ESR2 haplotype 1 and noncarriers of ESR1 haplotype 1 had a 3.5- and 1.8-fold increased risk of vertebral and fragility fractures (p(interaction) = 0.10). Such effects and interactions were stronger in women homozygous for the IGF1 192-bp allele, with 9.3-fold increased risk (p(interaction) = 0.002) for vertebral and 4.0-fold increased risk (p(interaction) = 0.01) for fragility fractures. Multilocus interaction analyses of fracture endured correction for multiple testing using Monte-Carlo simulations (p(interaction) = 0.02 for vertebral and p(interaction) = 0.03 for fragility fractures). Similar patterns of interaction were observed for BMD, cortical thickness, bone strength (section modulus), and instability (buckling ratio). In men, no such effects were observed. CONCLUSIONS: Variants of ESR2 alone and in interaction with ESR1 and IGF1 influence the risk of fracture in postmenopausal women. These findings reinforce the polygenic and complex character of osteoporosis.

Aged↗

A common disease haplotype segregating in spinocerebellar ataxia 2 (SCA2) pedigrees of diverse ethnic origin.

The identification of a CAG trinucleotide repeat expansion, located within the coding sequence of the ataxin-2 gene, as the mutation underlying spinocerebellar ataxia 2 (SCA2) has facilitated direct investigation of pedigrees previously excluded from linkage analysis due to insufficient size or pedigree structure. We have previously described the identification of the ancestral disease haplotype segregating in the Cuban founder population used to assign the disease locus to chromosome 12q23-24.1. We now report evidence for the segregation of the identical core haplotype in pedigrees of diverse ethnic origin from India, Japan and England, established by the analysis of the loci D12S1672 and D12S1333 located 20kb proximal and 200 kb distal to the triplet repeat motif respectively. Interpretation of this data is suggestive that for these pedigrees at least, the mutation has arisen on a single ancestral or predisposing chromosome.

Alleles↗

Structure, expression, and chromosomal localization of the mouse Atox1 gene.

Copper trafficking in eukaryotes involves small proteins termed metallochaperones, which mediate copper delivery to specific intracellular sites. Previous studies in yeast and human cell lines have suggested that Atox1 plays a critical role in copper delivery to the secretory pathway. In the present study, a mouse Atox1 (mAtox1) cDNA was cloned and shown to encode an open reading frame with 85% amino acid identity to human Atox1. RNA blot analysis revealed that mAtox1 was expressed as a single transcript in multiple tissues, and immunoblotting indicated that the relative abundance of mAtox1 mRNA directly correlated with mAtox1 protein. Analysis of the mAtox1 gene locus revealed a genomic structure with four exons encompassing a total of 14.5 kb. RFLP and haplotype analyses indicated that the mAtox1 locus was tightly linked to the Trhr and D15Bir7 loci on mouse chromosome 15. Taken together, these data reveal marked evolutionary conservation of Atox1 structure and provide a genomic organization and localization that will aid in the genetic deciphering of the molecular role of this protein in copper homeostasis.

Amino Acid Sequence↗

Inference on haplotype effects in case-control studies using unphased genotype data.

A variety of statistical methods exist for detecting haplotype-disease association through use of genetic data from a case-control study. Since such data often consist of unphased genotypes (resulting in haplotype ambiguity), such statistical methods typically apply the expectation-maximization (EM) algorithm for inference. However, the majority of these methods fail to perform inference on the effect of particular haplotypes or haplotype features on disease risk. Since such inference is valuable, we develop a retrospective likelihood for estimating and testing the effects of specific features of single-nucleotide polymorphism (SNP)-based haplotypes on disease risk using unphased genotype data from a case-control study. Our proposed method has a flexible structure that allows, among other choices, modeling of multiplicative, dominant, and recessive effects of specific haplotype features on disease risk. In addition, our method relaxes the requirement of Hardy-Weinberg equilibrium of haplotype frequencies in case subjects, which is typically required of EM-based haplotype methods. Also, our method easily accommodates missing SNP information. Finally, our method allows for asymptotic, permutation-based, or bootstrap inference. We apply our method to case-control SNP genotype data from the Finland-United States Investigation of Non-Insulin-Dependent Diabetes Mellitus (FUSION) Genetics study and identify two haplotypes that appear to be significantly associated with type 2 diabetes. Using the FUSION data, we assess the accuracy of asymptotic P values by comparing them with P values obtained from a permutation procedure. We also assess the accuracy of asymptotic confidence intervals for relative-risk parameters for haplotype effects, by a simulation study based on the FUSION data.

Algorithms↗

A high-resolution multistrain haplotype analysis of laboratory mouse genome reveals three distinctive genetic variation patterns.

Understanding of the structure and the origin of genetic variation patterns in the laboratory inbred mouse provides insight into the utility of the mouse model for studying human complex diseases and strategies for disease gene mapping. In order to address this issue, we have constructed a multistrain, high-resolution haplotype map for the 99-Mb mouse Chromosome 16 using approximately 70,000 single nucleotide polymorphism (SNP) markers derived from whole-genome shotgun sequencing of five laboratory inbred strains. We discovered that large polymorphic blocks (i.e., regions where only two haplotypes, thus one SNP conformation, are found in the five strains), large monomorphic blocks (i.e., regions where the five strains share the same haplotype), and fragmented blocks (i.e., regions of greater complexity not resembling at all the first two categories) span 50%, 18%, and 32% of the chromosome, respectively. The haplotype map has 98% accuracy in predicting mouse genotypes in two other studies. Its predictions are also confirmed by experimental results obtained from resequencing of 40-kb genomic sequences at 21 distinct genomic loci in 13 laboratory inbred strains and 12 wild-derived strains. We demonstrate that historic recombination, intra-subspecies variations and inter-subspecies variations have all contributed to the formation of the three distinctive genetic signatures. The results suggest that the controlled complexity of the laboratory inbred strains may provide a means for uncovering the biological factors that have shaped genetic variation patterns.

Alleles↗

Geographic distribution of chloroplast variation in Italian populations of beech (Fagus sylvatica L.).

The distribution of chloroplast DNA (cpDNA) variation in Italian beech ( Fagus sylvatica L.) populations was studied using PCR-RFLP and microsatellite markers. In total, 67 populations were analysed, and 14 haplotypes were identified by combining the two marker types. A remarkable subdivision of cpDNA diversity in Italian beech was found, as indicated by a high level of genetic differentiation ( G(st)=0.855). The highest level of total haplotype diversity ( h(t)=0.822) was estimated for southern Italian populations. The highest number of haplotypes was found in the central-southern region of the peninsula. The nested clade analysis provided evidence for past fragmentation events that may have been occurred during the Quaternary glaciations and had a major role in defining the genetic structure of the central-southern Italian beech populations. Only one haplotype apparently spread towards the north of Italy along the Apennine chain and reached the Italian slope of the western part of the Alps (Maritime Alps, Liguria). All haplotypes found along the Apennines remained trapped in the Italian peninsula. Southern and central Italy represent hotspots of haplotype diversity for Italian beech.

Analysis of Variance↗

Genetic heterogeneity of Bardet-Biedl syndrome in a distinct Canadian population: evidence for a fifth locus.

Bardet-Biedl syndrome (BBS) is a rare, autosomal recessive disease characterized by retinal dystrophy, renal structural abnormalities, obesity, dysmorphic extremities, and hypogenitalism in males. BBS is genetically heterogeneous with four known loci: BBS1 (11q), BBS2 (16q), BBS3 (3p), and BBS4 (15q). The prevalence of BBS in Newfoundland is approximately 10-fold greater than in Switzerland (1:160,000) and similar to the prevalence among the Bedouin of Kuwait (1:13,500). A population-based genetic survey was performed on 17 BBS families from the island portion of the province of Newfoundland, a comparatively isolated region of Canada. The families in the study had a total of 36 well-documented, affected individuals with 12 families having 2 or more affected individuals. Linkage at each of the four known loci was tested with two-point linkage and haplotype analysis. Three of the 17 kindreds showed linkage to 11q, 1 to 16q, and 1 to 3p. The latter is the first BBS3 family identified in a population of northern European descent. Six families remain undetermined because of poor pedigree structure or inconclusive haplotype analyses. Six families were excluded from all four known BBS loci, indicating that there is at least a fifth BBS locus (BBS5).

Abnormalities, Multiple↗

Gene flow and population history in high dispersal marine invertebrates: mitochondrial DNA analysis of Holothuria nobilis (Echinodermata: Holothuroidea) populations from the Indo-Pacific.

The sea cucumber, Holothuria nobilis, has a long-lived planktotrophic larvae, and previous allozyme surveys have suggested that high dispersal is realized. In contrast, recent ecological studies indicate that dispersal is low. To reconcile these data, and to investigate the evolution of this Indo-Pacific species, we screened geographical variation in 559 bp of a mitochondrial gene (COI) in 360 samples from the Australasian region and La Réunion. Sequences from La Réunion differed by > 7% from others and may constitute another species. Haplotype diversity in other samples was high (0.942, SD = 0.007), but haplotypes were closely related (mean nucleotide diversity: 0.0075, SD = 0.0041). AMOVA, pairwise FST values and exact tests did not detect significant population structure. Nested clade analysis showed that one of two main clades was over-represented in west Australia, whereas the other was more common in the northern Great Barrier Reef. Isolation-by-distance was identified as the main determinant of population structure at several clade levels. Contiguous range expansion was inferred for evolutionary older clade levels and this may correspond to a late Pleistocene (88 000-193 000 years ago) population expansion inferred from haplotype mismatch distributions. Thus, the population genetic structures detected are likely to be formed prior to the last ice age, with some indications for high dispersal on shorter time scales.

Analysis of Variance↗

Introgression among maternal lineages inferred from complete mitogenomes and molecular dating helps resolve phylogeography of European roe deer.

BACKGROUND: The European roe deer (Capreolus capreolus) is one of the most widespread ungulates in Europe, with a phylogeographic structure mainly shaped by Pleistocene glacial cycles and secondary contacts with the Siberian roe deer (C. pygargus). METHODS: We sequenced 52 complete mitogenomes of C. capreolus from Slovenia, Poland and France, and combined them with 24 publicly available sequences of C. capreolus and C. pygargus, yielding an alignment of 76 genomes representing 59 haplotypes (42 from C. capreolus and 17 from C. pygargus). Phylogeographic structure was assessed using a median-joining network, and divergence times were estimated using a time-calibrated Bayesian phylogeny based on mitochondrial coding regions, incorporating published ancient C. pygargus mitogenomes. We additionally screened mitochondrial protein-coding genes for selection. RESULTS: The haplotype network recovered the three major European roe deer clades (Eastern, Central, and Western) and detected Central-clade haplotypes in France. Two Polish haplotypes (Cp9 and Cp10), detected in C. capreolus, clustered within the C. pygargus mitochondrial lineage, supporting mitochondrial introgression. Time-calibrated phylogenies placed introgressed haplotypes within established C. pygargus lineages. Selection analyses provided limited evidence for episodic positive selection restricted to a small number of codons. CONCLUSIONS: Whole mitogenomes improve resolution of roe deer phylogeography and reveal introgressed maternal lineages, while time-calibrated phylogenies and selection tests add evolutionary context for interpreting mtDNA diversity in genus Capreolus.

Animals↗

Further evidence for recombination between mouse hemoglobin beta b1 and b2 genes based on the nucleotide sequences of intron, UTR, and intergenic spacer regions.

Nucleotide sequences of the intron regions and UTRs (Untranslated regions) of the hemoglobin beta adult genes, b1 and b2, and of the intergenic spacer region were determined for mouse strains representing the d, p, and w1 hemoglobin haplotypes defined by protein electrophoretic analyses. The hypothesis of recombination of the b1 and b2 genes between the d and w1 haplotypes previously reported in the cDNA nucleotide sequences was confirmed by neighbor-joining analyses of the intron regions and UTRs within the b1 and b2 genes, suggesting that all of the structures of hemoglobin beta adult genes support the hypothesis that the p haplotype was established by hybridization between d and w1 haplotype mice. The resultant recombinant of the p haplotype was found to have a d-like b1 gene and a w1-like b2 gene. In addition to the possible recombination, a break point was suggested around 2-3 kb downstream of the b1 gene within the intergenic spacer region, despite the absence of clear properties that could stimulate the recombination machinery. Some large insertions or deletions (indels) specific to the p or d haplotypes were located within the intergenic spacer region, in which the 1010-bp indel specific to the p haplotype was shared by all examined strains representing the p haplotype.

Animals↗

Genetic exchange by recombination or reassortment is infrequent in natural populations of a tripartite RNA plant virus.

Two hundred seventeen field isolates of cucumber mosaic cucumovirus (CMV), sampled from 11 natural populations, were typed by RNase protection assay (RPA) using probes from the genomic RNAs of strains in subgroup I and in subgroup II of CMV strains. Most (85%) of the analyzed isolates belonged to subgroup I. For these subgroup I isolates, only two clearly different RPA patterns, A and B, were found for each of four probes representing RNA1, RNA2, and each of the two open reading frames in RNA3. On the basis of these RPA patterns for each probe, different haplotypes were defined. The frequency composition for these haplotypes differed for the various analyzed populations, with no correlation with place or year of sampling. This genetic structure corresponds to a metapopulation with local extinctions and recolonizations. Most subgroup I isolates (73%) belonged to haplotypes with RPA pattern A (type 1) or B (type 2) for all four probes. A significant fraction of subgroup I isolates (16%) gave evidence of mixed infections with these two main types, from which genetic exchange could occur. Genetic exchange by segment reassortment was seen to occur: the fraction of reassortant isolates was 4%, reassortment did not occur at random, and reassortants did not become established in the population. Thus, there is evidence of selection against reassortment between types 1 and 2 of subgroup I isolates. Aphid transmission experiments with plants doubly infected with type 1 and type 2 isolates gave further evidence that reassortment is selected against in CMV. Genetic exchange by recombination was detected for RNA3, for which two RPA probes were used. Recombinant isolates amounted to 7% and also did not become established in CMV populations. Sequence analyses of regions of RNA1, RNA2, and RNA3 showed that there are strong constraints to maintain the encoded sequence and also gave evidence that these constraints may have been different during divergence of types 1 and 2 and, later on, during diversification of these two types. Constraints to the evolution of encoded proteins may be related to selection against genetic exchange. Our data, thus, do not favor current hypotheses that explain the evolution of multipartite viral genomes to promote genetic exchange.

Genome, Viral↗

Defective, deleted or converted CYP21B gene and negative association with a rare restriction fragment length polymorphism allele of the factor B gene in congenital adrenal hyperplasia.

Defects in the enzyme, steroid 21-hydroxylase, result in congenital adrenal hyperplasia (CAH), a common autosomal recessive disorder of cortisol biosynthesis. The gene encoding this protein (CYP21B) and a closely linked pseudogene (CYP21A) have been mapped in the HLA complex on chromosome 6p, adjacent to the complement genes C4B and C4A, about 80 kb from the factor B gene. Molecular analyses of patients with CAH have shown that the cause of the defect may be either a deletion, a point mutation or a conversion of the active gene. Linkage of the disease to HLA has previously been studied by several groups. We have analyzed DNAs from patients with classical and non-classical CAH and from their family members, by probing with CYP21, C4 and BF cDNAs. In 70% of the CAH haplotypes studied, the defective CYP21B gene was indistinguishable from its structurally intact corresponding gene in Southern blot analysis, and presumably bore point mutations. In the remaining chromosomes, evidence for gene conversions, deletions and various deleterious mutations of the CYP21B gene is given. Moreover, our linkage studies show that a polymorphic TaqI cleavage site in the factor B gene, recently described by us, may be a new and useful genetic marker, because we found this TaqI restriction site only in unaffected haplotypes carrying functional CYP21B genes and, therefore, in negative association with the defective CYP21B gene.

Adrenal Hyperplasia, Congenital↗

Comparative phylogeography of Baileys' pocket mouse (Chaetodipus baileyi) and the Peromyscus eremicus species group: historical vicariance of the Baja California Peninsular Desert.

Phylogenetic analysis of 699 bp of the mitochondrial DNA (mtDNA) COIII and 450 bp of the cytochrome b genes among 14 species of coarse-haired pocket mice (Heteromyidae: Chaetodipus) corroborated previous indications that genetic divergence between species and species groups within the genus is generally very high, suggesting old times of divergence, and that the nominal species C. baileyi represents a highly divergent lineage within the genus, with no closely related extant sister species. Analysis of phylogeographic structure among 51 individuals from 12 localities throughout the geographic range of C. baileyi revealed three geographically separate mtDNA haplotype lineages. The oldest split separates populations east and west of the Colorado River, a pattern that is congruent with chromosomal and allozyme electrophoretic evidence. We consider the western populations to represent a distinct species, C. rudinoris. Within C. rudinoris, mtDNA haplotypes are further subdivided into northern and southern lineages along the Baja California Peninsula. Comparison of phylogeographic structure in the baileyi species group and the codistributed Peromyscus eremicus species group implies two points of codivergence and thus supports two historical vicariance hypotheses proposed for biotas distributed across the peninsular and continental warm deserts: a late Neogene (3 Ma) northern extension of the Sea of Cortéz and a mid-Pleistocene (1 Ma) midpeninsular seaway across Baja California.

Animals↗

Molecular analysis of the HLA-DR5 haplotype.

A panel of eleven HLA-DR5 homozygous lymphoblastoid cell lines was investigated for structural heterogeneity on the product level. HLA class II antigens were isolated by immunoprecipitation with different anti-class II monoclonal antibodies and separated by two-dimensional (2-D) gel electrophoresis. As a result, three distinct DRB1, one commonly expressed DRB3, and two distinct DQ gene products could be identified that combined to four different haplotypes associated with HLA-DR5. A hitherto serologically undetected split of HLA-DRw11 was presented by three cell lines. HLA-DRw11 and HLA-DRw12 were found to be related allospecifities that differ only in their DRB1 locus products, but are closely associated with the supertypic DRB3 allele HLA-DRw52b and with HLA-DQw7. The DRB3 alleles HLA-DRw52a and DRw52c were not detected in our cell line panel, indicating that these supertypic determinants are in negative linkage disequilibrium with HLA-DR5. Our data suggest that intra HLA-DR/DQ crossing-over events contribute to the development of the HLA class II polymorphism. Evidence is presented that the T cell defined HLA-D allospecifities are commonly determined by DRB1 and DQ gene products.

Amino Acids↗

Population genetic structure of two ecologically distinct Amazonian spiny rats: separating history and current ecology.

Population history and current demographic and ecological factors determine the amount of genetic variation within and the degree of differentiation among populations. Differences in the life history and ecology of codistributed species may lead to differences in hierarchical population genetic structure. Here, we compare patterns of genetic diversity and structure of two species of spiny rats in the genus Proechimys from the Rio Jurui of western Amazonian Brazil. Based on the ecological and life-history differences between the two species, we make predictions as to how they might differ in patterns of genetic diversity and structure. We use mitochondrial sequence data from the cytochrome b gene to test these predictions. Although both species maintain nearly the same number of mitochondrial haplotypes across the sampled range, they differ in levels of genetic diversity and geographic structure. Patterns of gene flow are also different between the two species with average M-values of nearly three in P. steerei and less than one in P. simonsi. Our initial predictions are largely upheld by the genetic data and where conflicting hypotheses arise, we suggest further studies that may allow us to distinguish among evolutionary scenarios. Separating the effects of history and ongoing demography on patterns of genetic diversity is challenging. Combining genetic analyses with field studies remains essential to disentangling these complex processes.

Animals↗