Microsatellite Variation in Two Populations of Free-Ranging Yellow Baboons (Papio hamadryas cynocephalus)

We investigated genetic variation at six microsatellite (simple sequence repeat) loci in yellow baboons (Papio hamadryas cynocephalus) at two localities: the Tana River Primate Reserve in eastern Kenya and Mikumi National Park, central Tanzania. The six loci (D1S158, D2S144, D4S243, D5S1466, D16S508, and D17S804) were all originally cloned from and characterized in the human genome. These microsatellites are polymorphic in both baboon populations, with the average heterozygosity across loci equal to 0.731 in the Tana River sample and 0.787 in the Mikumi sample. The genetic differentiation between the two populations is substantial. Kolmogornov–Smirnov tests indicate that five of the six loci are significantly different in allele frequencies in the two populations. The mean F _ST across loci is 0.069, and Shriver's measure of genetic distance, which was developed for microsatellite loci (Shriver et al., 1995), is 0.255. This genetic distance is larger than corresponding distances among human populations residing in different continents. We conclude that (a) the arrays of alleles present at these six microsatellite loci in two geographically separated populations of yellow baboons are quite similar, but (b) the two populations exhibit significant differences in allele frequencies. This study illustrates the potential value of human microsatellite loci for analyses of population genetic structure in baboons and suggests that this approach will be useful in studies of other Old World monkeys.     

Characterization of microsatellite loci in the Kaka,Nestor meridionalis

Eight microsatellite loci were characterized from the Kaka (Nestor meridionalis), a New Zealand parrot, using a polymerase chain reaction‐based isolation technique. Locus‐specific primers were used to genotype nine Kaka populations and tested on 25 other species of parrot. The number of alleles observed within Kaka ranged from one to 16 in the 12–126 individuals screened and two loci exhibited greater than 60% heterozygosity. Furthermore, these primers are likely to be useful in population‐level studies of two other New Zealand parrots.     

Genetic variation and genotypic diversity in Epipactis helleborine populations from NE Poland

Enzyme electrophoreses were used to estimate genetic variation in five populations of Epipactis helleborine from two National Parks (Biebrza and Wigry) in northeast Poland. It has been proved that populations from these two regions differed in genetic structure, with the populations belonging to the Biebrza group having a higher level of genetic variation than those from Wigry. The number of polymorphic loci (P) ranged from 18.2% to 40.9% and the mean number of alleles per polymorphic locus (Ap) from 2.25 to 2.80. Although the observed heterozygosity (H_o) was lower than the expected one (H_e) in each population, the values of H_o and H_e were 2–3 times lower in the populations from Wigry than in those from Biebrza. Excluding the LUK population with the smallest genotypic diversity, the majority of 345 distinct multilocus genotypes occurred only once, sporadically 2–4 times in each population and their frequency ranged from 0.2% to 3.7%. Moreover, factors shaping genetic structure of E. helleborine and their intensity varied in the populations studied. Reproduction from seeds seems to influence greatly the genetic variation of the populations from the Biebrza National Park, while an assortative mating between related individuals or population size appears to be more important in the case of the populations from the Wigry National Park.     

Genetic differentiation of starling (Sturnus vulgaris: Aves) populations in New Zealand and Great Britain

Several hundred starlings (Sturnus vulgaris) were introduced to New Zealand from Great Britain during1860–1880. Allozymic variation at 24 loci was analysed in winter populations sampled at six localities in each country. New Zealand samples had fewer alleles per locus but the same mean heterozygosity (3% per locus) and proportion of polymorphic loci as did British samples. Winter populations in Britain contain European migrants and were genetically homogeneous. Paradoxically, genetic distances among derived New Zealand populations, and between New Zealand and Great Britain were much greater, similar in magnitude to those observed among allopatric populations in other avian species. The geographical pattern of genetic variation in New Zealand suggests that reproductive isolation of populations and random drift have contributed to the development of population differentiation.     

Genetic Variation in Remnant Populations of the Woolly Spider Monkey (Brachyteles arachnoides)

The muriqui or woolly spider monkey (Brachyteles arachnoids) is an endangered primate endemic to the Atlantic Forest of Brazil, <5% of which remains. The known muriqui population consists of <700 individuals separated into approximately 15 geographically isolated forest fragments. I present data on the distribution of genetic variation within and between two such remnant populations (FE and FBR) and summarize the implications of these results for long-range management of species genetic diversity. Eleven of 32 allozyme loci were polymorphic, representing an overall level of polymorphism of 34.4% and a mean heterozygosity per locus of 11%. Both values are among the highest reported for New World monkeys. Genetic differentiation between the two localities is highly significant (F_ST = 0.413, p < 0.001). Genetic distance between them is an order of magnitude greater than that between other populations of platyrrhine subspecies, but this could be an artifact of the small sample size from FBR. High levels of genetic diversity apparently characteristic of this species persist because (1) fragmentation and size reduction of muriqui populations has occurred very rapidly relative to the muriqui life span—although both polymorphism and heterozygosity were lost between generations in the largest population, the high genetic diversity present in the parent population was still in evidence; and (2) genetic diversity before population fragmentation by human activity was not distributed uniformly throughout the species' historic distribution. Thus, remnant muriqui populations are important genetic reservoirs of alleles that are unique or rare in the species gene pool as a whole. These results emphasize the need for the integration of conservation management efforts throughout the species range.     

Genetic differentiation of theErigeron species (Asteraceae) in the Alps: A case of unusual allozymic uniformity

Allozyme variation was studied in all nine diploidErigeron species known from the Alps:E. alpinus, E. neglectus, E. polymorphus, E. candidus, E. uniflorus, E. atticus, E. gaudinii, E. acer, andE. angulosus. A total of 248 individuals from 24 natural populations was investigated using starch gel electrophoresis. Seven enzymes and 13 loci were assessed. Genetic variation within populations was low with the proportion of polymorphic loci ranging from 0.0–0.385, and average number of alleles per polymorphic locus from 2.0–2.5. In general, 70–100% of the genetic variation was attributed to between population differences. Mean genetic identities for pair-wise comparisons of populations averaged 0.893 within species, and 0.890 among species. Interspecific genetic variation of populations usually did not exceed intraspecific variation. It was concluded that theErigeron species from the Alps may have arisen by recent speciation probably during the epoches of glaciation. Morphological and ecological differences between species seem to be based on few gene loci.     

Development of Novel Microsatellite DNA Markers from the Pacific Oyster Crassostrea gigas

We document the potential of novel microsatellites as a genetic tool in furthering our understanding of the Crassostrea gigas genetic structure. From the microsatellite-enriched libraries we constructed, 123 repeat regions that had sufficient sequence information to design polymerase chain reaction primer sets were isolated. From these, 9 primer pairs were screened in a C. gigas population of 67 individuals to evaluate the genetic variability. All but 1 of the 9 loci showed allelic variation (number of alleles, 2–20; observed heterozygosity, 0.119–0.925; unbiased expected heterozygosity, 0.139–0.914). Considerable discrepancy of genotypic proportions from the Hardy-Weinberg equilibrium was observed at 1 locus with an apparent heterozygote deficiency. Several loci were successfully amplified in 3 other related species with the appropriate allele size: 6 loci in C. sikamea, 4 loci in C. ariakensis, and 5 loci in C. nippona.     

Relationships among genetic distance,forage yield and heterozygosity in isogenic diploid and tetraploid alfalfa populations

Isogenic diploid and tetraploid alfalfa (Medicago sativa L.) was studied with molecular markers to help understand why diploid performance and breeding behavior does not always predict that of tetraploids. In a previous study of partially heterozygous alfalfa genotypes, we detected a low correlation between yields of isogenic diploid (2x) and tetraploid (4x) single-cross progenies, and genetic distances were more highly correlated with yields of tetraploids than diploids. These differences may be related to the level of RFLP heterozygosity expected among progenies derived from heterozygous parents at the two ploidy levels. The objectives of this study were to determine the relationships among genetic distance, forage yield and heterozygosity in isogenic 2 x and 4 x alfalfa populations. Four diploid genotypes were chromosome doubled to produce corresponding isogenic autotetraploids, and these genotypes were mated in 4 × 4 diallels to produce 6 single-cross families at each ploidy level for field evaluation. Allele compositions of parents were determined at 33 RFLP loci by monitoring segregation of homologous restriction fragments among individuals within progenies, and these were used to estimate RFLP heterozygosity levels for all single-cross progenies at both ploidy levels. RFLP heterozygosity rankings were identical between progenies of isogenic diploid and tetraploid parents; but significant associations (P < 0.05) between estimated heterozygosity levels and forage yield were detected only at the tetraploid level. Since tetraploid families were nearly 25% more heterozygous than the corresponding diploid families, inconsistencies in the association between molecular marker diversity and forage yields of isogenic 2 x and 4 x single crosses may be due to recessive alleles that are expressed in diploids but masked in tetraploids. The gene action involved in heterosis may be the same at both ploidy levels; however, tetraploids benefit from greater complementary gene interactions than are possible for equivalent diploids. Present address: AgResearch Grasslands, New Zealand Pastoral Agriculture Research Institute, Palmerston North, New Zealand     

Genetic differentiation among populations ofArabis serrata (Brassicaceae) along its geographic distribution

Levels and distribution of genetic variation were investigated in ten populations of the perennialArabis serrata distributed along a latitudinal gradient throughout Japan. Populations of this endemic species occupy predominantly three types of habitats: limestone and derived soils, volcanic and disturbed sites. Previous studies showed that plants ofA. serrata are differentiated in morphological and ecological traits under both natural conditions and common garden experiments suggesting genetic differentiation among populations. To assess the degree of genetic differentiation under different habitats ofA. serrata populations, we analyzed the isozyme genetic structure. Ten populations, located in mountains of central and northern Honshu and Hokkaido, were analyzed by starch gel enzyme electrophoresis. Fourteen loci of eight enzymes were resolved and six loci were monomorphic for all the populations. Populations sampled maintain low levels of genetic variation (P=0.16;H=0.05;A=1.16) compared to that maintained by other outcrossing seed plants. In some cases, few or no heterozygous individuals were detected, and consequently, mean observed heterozygosity was zero or near zero. Six (29%) of the fixation indices,F, estimated deviated significantly from Hardy Weinberg genotypic expectations indicating a deficiency of heterozygotes in most of the cases. The mean genetic identity (Nei'sI) between population pairs was 0.852 and indicates a moderate level of genetic differentiation among populations.Arabis serrata has most of its genetic variation distributed among rather than within populations. The among-population component of the total genetic diversity (G _ST mean value) was 0.416, indicating genetic differentiation between populations. There groups of populations were recognized in an unrooted tree generated by the Neighbor-Joining method. These results suggest groups of populations differentiated regionally. Estimates of interpopulational gene flow (Nm) were very variable (range 0.049–3.718) with a meanNm=1.203 for all populations.     

MORPHOLOGICAL AND GENETIC VARIABILITY IN PLANTAGO CORDATA (PLANTAGINACEAE), A THREATENED AQUATIC PLANT

Morphological and genetic variation were studied in Plantago cordata Lam., an imperiled aquatic plant. The existence of distinct seasonal morphs was confirmed by numerical morphological analyses of specimens from 53 populations. Plants from two North Carolina populations possessed leaves that were significantly shorter, narrower, and fewer-veined than populations in other portions of the species range. Genetic variation within and among ten populations in seven states/provinces (Illinois, Missouri, New York, North Carolina, Ohio, Ontario, and Wisconsin) was examined electrophoretically. The species is an apparent allopolyploid with fixed heterozygosity observed at 67% of the loci surveyed. Electrophoretic variation was mostly partitioned among populations. The genetic identity among populations was high except for North Carolina populations which differed at 27% of the loci surveyed.     

Molecular evidence for historical and recent population size reductions of tiger salamanders (Ambystoma tigrinum) in Yellowstone National Park

Population declines caused by natural and anthropogenic factors can quickly erode genetic diversity in natural populations. In this study, we examined genetic variation within 10 tiger salamander populations across northern Yellowstone National Park in Wyoming and Montana, USA using eight microsatellite loci. We tested for the genetic signature of population decline using heterozygosity excess, shifts in allele frequencies, and low ratios of allelic number to allelic size range (M-ratios). We found different results among the three tests. All 10 populations had low M-ratios, five had shifts in allele frequencies and only two had significant heterozygosity excesses. These results support theoretical expectations of different temporal signatures among bottleneck tests and suggest that both historical fish stocking, recent, sustained drought, and possibly an emerging amphibian disease have contributed to declines in effective population size.     

Low genetic diversity and significant population structuring in the relict Amentotaxus argotaenia complex (Taxaceae) based on ISSR fingerprinting

Amentotaxus, a genus of the Taxaceae, represents an ancient lineage that has long existed in Eurasia. All Amentotaxus species experienced frequent population expansion and contraction over periodical glaciations in Tertiary and Quaternary. Among them, Amentotaxus argotaenia complex consists of three morphologically alike species, A. argotaenia, Amentotaxus yunnanensis, and Amentotaxus formosana. This complex is distributed in the subtropical region of mainland China and Taiwan where many Pleistocene refugia have been documented. In this study, genetic diversity and population structuring within and between species were investigated based on the inter-simple sequence repeats (ISSR) fingerprinting. Mean genetic diversity within populations was estimated in three ways: (1) the percentage of polymorphic loci out of all loci (P) (2) Neis unbiased expected heterozygosity (He), and (3) Shannons index of phenotypic diversity. For a total of 310 individuals of 15 populations sampled from the three species, low levels of ISSR genetic variation within populations were detected, with P=4.66–16.58%, He=0.0176–0.0645 and Hpop=0.0263–0.0939, agreeing with their seriously threatened status. AMOVA analyses revealed that the differences between species only accounted for 27.38% of the total variation, whereas differences among populations and within populations were 57.70 and 14.92%, respectively, indicating substantial isolation between the patch-like populations. A neighbor-joining tree identified a close affinity between A. yunnanensis and A. formosana. Genetic drift due to small population size, plus limited current gene flow, resulted in significant genetic structuring. Low levels of intrapopulational genetic variation and considerable interpopulational divergence were also attributable to demographic bottlenecks during and/or after the Pleistocene glaciations.     

Genetic diversity in the blackberry rust pathogen, Phragmidium violaceum, in Europe and Australasia as revealed by analysis of SAMPL

Indigenous to Europe, the blackberry rust fungus Phragmidium violaceum was introduced to Australia and subsequently appeared in New Zealand, with the most recent authorised introductions to Australia specifically for the biological control of European blackberry. Markers for ‘selective amplification of microsatellite polymorphic loci’ (SAMPL) were developed for studying the population genetics of P. violaceum. Modification of one of the two SAMPL primers with a HaeIII adapter (H) revealed significantly greater levels of genetic variation than primers used to generate AFLPs, the latter revealing little or no variation among 25 Australasian and 19 European isolates of P. violaceum. SAMPL was used to describe genetic variation among these 44 isolates of P. violaceum from 51 loci generated using primer pairs (GACA)₄ + H–G and R1 + H–G. The European isolates were more diverse than Australasian isolates, with 37 and 22 % polymorphic loci, respectively. Cluster analysis revealed geographic clades, with Australasian isolates forming one cluster separated from two clusters comprising the European isolates. However, low bootstrap support at these clades suggested that Australian isolates had not differentiated significantly from European isolates since the first record of P. violaceum in Australia in 1984. In general, the results support two hypotheses. First, that the population of P. violaceum in Australia was founded from a subset of individuals originating from Europe. Second, that P. violaceum in New Zealand originated from the Australian population of P. violaceum, probably by wind dispersal of urediniospores across the Tasman Sea. The application of SAMPL markers to the current biological control programme for European blackberry is discussed.     

Microsatellite analysis of the genetic structure of captive forest musk deer populations and its implication for conservation

Forest musk deer (Moschus berezovskii) are rare as a result of poaching for musk and habitat loss. Some captive populations of forest musk deer have been established for decades in China. However, little genetic information is available for conservation management. In this paper, genetic variations, population structures, and the genetic bottleneck hypothesis were examined using 11 microsatellite loci from captive populations in Miyalo, Jinfeng and Maerkang in Sichuan Province, China. Estimates of genetic variability revealed substantial genetic variation in the three populations. A total of 142 different alleles were observed in 121 forest musk deer and the effective number of alleles per locus varied from 6.76 to 12.95. The average values of observed heterozygosity, expected heterozygosity, and Nei's expected heterozygosity were 0.552, 0.899 and 0.894 respectively. The overall significant (P < 0.001) deficit of heterozygotes because of inbreeding within breeds amounted to 34.5%. The mean F_ST (P < 0.001) showed that approximately 90.2% of the genetic variation was within populations and 9.8% was across populations. The UPGMA diagram, based on Nei's unbiased genetic distance, indicated that the three populations were differentiated into two different groups and it agreed with their origin and history. Bottleneck tests indicated that all three populations have undergone a population bottleneck, suggesting a small effective population size. Acknowledging that the genetic structure of populations has crucial conservation implications, the present genetic information should be taken into account in management plans for the conservation of captive forest musk deer.     

Genetic variation within the Hereford breed of cattle

Genetic differentiation among Hereford populations from Britain, Ireland, Sweden, Canada and New Zealand together with six other beef breeds was assessed using blood type polymorphisms. Changes in the genetic structure of the British Hereford population over time were also examined. Loci surveyed were seven red cell antigen systems (A, B, C, F, L, S, Z), and two serum protein loci (transferrin and albumin). Within group variation was measured by the average expected heterozygosity, and between group relationships by genetic distance. There was significant genetic differentiation among Hereford populations from different countries. Differences between Hereford groups, however, were not as large as differences between breeds. There were also significance differences among British herds. The proportion of Canadian genes in the British 'hybrid' population was estimated to have increased from 0·42 (±0·34) in the 1970s to 0·98 (±0·11) in the 1990s. Canadian Hereford groups were found to be less heterozygous than other groups, and replacement of the British population with Canadian animals may lead to loss of variation. Breeding strategies that preserve original native genes in British Hereford populations should be considered by commercial breeders, in order to prevent the long-term loss of genetic variation within the breed.     

Allozyme Diversity and Genetic Divergence of the Dolly Varden Salvelinus malma Walbaum from the Kuril Islands

Genetic variation was studied in the southern subspecies of the Asian Dolly Varden Salvelinus malma krascheninnikovi from the Kuril Islands. Thirty-six genetic loci controlling 19 enzyme systems were analyzed in 13 Dolly Varden populations from the Shumshu, Paramushir, Onekotan, Rasshua, Simushir, Urup, Iturup, and Kunashir islands. In the studied populations, the proportion of polymorphic loci was 35 to 85% and the mean heterozygosity was 0.104 to 0.173; populations from the Kunashir Island were characterized by maximum heterozygosity. In the island populations examined, significant interpopulation heterogeneity of allele frequencies was found for all studied population pairs. For the all island populations, the interpopulation diversity (G _ST = 0.188) was comparable to this parameter for the populations from the Kunashir Island only (G _ST = 0.170). Genetic distances between populations did not correlate with the corresponding geographical distances, which indicates the lack of a pronounced gene exchange between the island populations. Cluster analysis and multidimensional scaling based on genetic distances did not reveal clear groups among the studied populations but indicated greater similarity within the Iturup–Simushir–Urup–Paramushir group and a greater genetic divergence of the Kunashir, Onekotan, Rasshua, and especially Shumshu populations. In the Shumshu population, allele frequencies indicate the admixture of genes of the northern Dolly Varden. The observed pattern of genetic differentiation was probably caused largely by genetic drift under the conditions of a limited gene flow because of homing (which is typical of the Dolly Varden) and the presence of isolated nonanadromous populations. The population–genetic analysis of the Dolly Varden from the Kuril Islands does not give grounds to distinguish any other isolated char species in this region than S. malma, which is represented by the southern form S. m. krascheninnikovi with an admixture of the northern form S. m. malma in the Shumshu Island.     

Conservation genetics of bull trout: Geographic distribution of variation at microsatellite loci

We describe the genetic population structure of65 bull trout (Salvelinus confluentus)populations from the northwestern United Statesusing four microsatellite loci. Thedistribution of genetic variation as measuredby microsatellites is consistent with previousallozyme and mitochondrial DNA analysis. Thereis relatively little genetic variation withinpopulations (H ^S = 0.000 – 0.404,average H ^S = 0.186, but substantialdivergence between populations (F ^ST = 0.659). In addition, those populations that had low genetic variation forallozymes also tended to have low geneticvariation at microsatellite loci. Microsatellite analysis supports the existenceof at least three major geneticallydifferentiated groups of bull trout: (1)``Coastal' bull trout populations, (2) ``SnakeRiver' populations, which also include the JohnDay, Umatilla, and Walla Walla Rivers and, (3)populations from the upper Columbia River,primarily from the Clark Fork basin. Withinthe major assemblages, populations are furthersubdivided, primarily at the river basin level. Most of the genetic similarities we havedetected probably reflect patterns of historicisolation and gene flow. However, in somecases, genetic drift and low levels ofvariation appear to have influenced therelationships inferred from these data. Finally, we suggest using a hierarchicalapproach to direct management actions inspecies such as bull trout for which most ofthe genetic variation exists among populationsand local populations in close proximitytypically are genetically distinct.     

基于SSR标记探讨三种金花茶植物的遗传多样性和遗传结构

薄叶金花茶、小花金花茶和小瓣金花茶是三种濒危金花茶植物,为了解珍稀濒危植物遗传多样性和遗传结构,该研究利用微卫星标记对他们的7个种群共184个个体进行了遗传多样性和遗传结构分析。结果表明:11个位点共检测到等位基因92个。在物种水平上,小瓣金花茶平均等位基因数(N_A)为3.9、有效等位基因数(N_E)为2.328、观测杂合度(H_o)为0.520、期望杂合度(H_e)为0.501,高于薄叶金花茶和小花金花茶。在种群水平上,有效等位基因数(N_E)在1.788～2.466之间,期望杂合度(H_e)在0.379～0.543之间;种群间遗传分化系数(FST)在0.143 7～0.453 3之间,种群间基因流(N_m)在0.301 5～1.488 9之间。AMOVA分子变异分析显示65.72%的变异存在于种群内。三种金花茶具有较低水平的遗传多样性和高水平的种群间遗传分化。STRUCTURE和PCoA种群遗传结构分析结果将取样种群分为2组,即薄叶金花茶和小花金花茶大部分个体分为一组,小瓣金花茶大部分个体分为一组。现存所有种群应根据实际情况尽快采取就地保护或迁地保护措施。     

Analysis of genetic diversity in the endangered Hucho taimen from China

Hucho taimen are listed as endangered in China. The population size has declined recently, prompting an increase in the level of listing from grade three in 2002 to grade five in 2006. We analyzed the genetic diversity of wild populations using 17 microsatellite markers to establish a scientific basis for conservation of this species. We collected tissue samples from four populations in the Heilongjiang River basin: Huma River (HM), Hutou (HT), Haiqing (HQ), and Zhuaji (ZJ). A total of 21 loci were amplified, 18 of which were polymorphic. The number of alleles per locus ranged from 2 to 9 (mean: 4.1905). There were 13 highly polymorphic loci and 5 moderately polymorphic loci. Analysis of five genetic diversity parameters (Na, Ne, Ho, He, and PIC) suggested moderate levels of diversity within the populations. The populations were ranked HT > HQ > ZJ > HM, but the differences in diversity were not statistically significant (P > 0.05). A comparison of variation among all four populations suggested Hardy–Weinberg disequilibrium at 20% of the loci. Genetic differentiation (Fst) was 0.0644 and the gene flow among populations was estimated at 3.36 individuals per generation. The majority of diversity (93.88%) occurred among individuals within a population. In contrast, relatively little (6.12%) of the genetic diversity was distributed between the populations. An analysis of genetic differentiation and genetic distance between pairs of populations revealed that both parameters were higher in comparisons of the HM population to the HT, HQ, and ZJ populations than among the three latter populations. This suggests that the HM population has a distinct genetic structure. We hypothesize that habitat degradation and excessive fishing, not low genetic diversity, has caused the decline in H. taimen populations. However, this species should be protected from further declines in genetic diversity.     

Variation at isozyme loci inTriticeae

An electrophoretic comparison of variation at 16 presumptive isozyme gene loci was performed for 17 species from the tribeTriticeae. Included in the analysis were annuals and perennials, and self- and cross-pollinating species, representing the H, I, P, N, R, V, S, E, J, J₁J₂, A, B, and D genomes. Perennial species were found to contain a significantly (marginally, at the 5% level) higher proportion of polymorphic loci and level of heterozygosity, than annual species. There were no significant differences between self- and crosspollinating species. Across all species, mean heterozygosity levels ranged from 0–0.225 and the % polymorphic loci from 6.3–56.3%. Genetic distance estimates varied from 0.08–0.39 for congeneric species. Relationships were deduced between the 17 species using phenetic and cladistic analyses and compared with relationships inferred from other parameters such as morphology and nucleotide sequence data. In general, the trees derived from the various relationships were concordant; the evolutionary basis for minor discrepancies between trees is also discussed.