Genetic Distance Analysis Research Articles

Presumptive First Record of Myotis aurascens (Chiroptera, Vespertilionidae) from China with a Phylogenetic Analysis.

Bat groups have a high degree of species diversity, and the taxonomic status and phylogenetic relationships among bat species have always been research hotspots. Due to the fact that morphological characteristics do not always reflect the evolutionary relationships among species, mitochondrial DNA has been widely used in the study of species relationships due to its maternal inheritance pattern. Myotis aurascens has been suggested as a possible synonym for M. davidii. However, the status of this classification has been controversial. In this study, the morphological and molecular characteristics of a M. aurascens captured from Inner Mongolia, China, were analyzed to determine its taxonomic status. In terms of morphological features, the body weight was 6.33 g, the head and body length were 45.10 mm, the forearm length was 35.87 mm, and the tragus length was 7.51 mm. These values all fell within the species signature data range. Nucleotide skew analysis of the protein-coding genes (PCGs) suggested that only five PCGs (ND1, ND2, COX2, ATP8, and ND4) showed AT-skew value within the mitogenome of M. aurascens. Except for ND6, the GC-skew values of the other PCGs were negative, reflecting the preference for C and T bases compared to G and A bases. Molecular phylogenetic analyses based on mitochondrial PCGs indicated that M. aurascens was a distinct species from M. davidii and phylogenetically closer to M. ikonnikovi, M. alcathoe, and M. mystacinus. Genetic distance analysis also showed that M. aurascens and M. davidii were distantly related. Therefore, the integrated analysis demonstrated that M. aurascens should be considered a distinct species rather than a synonym of M. davidii. Our study could provide a reference for enriching species diversity and research on conservation in China.

Genetic and morphological characterization of United States tea (Camellia sinensis): insights into crop history, breeding strategies, and regional adaptability.

Multiple introductions of tea (Camellia sinensis) to the United States since the 1850s have resulted in US tea germplasm that are currently poorly characterized. To resolve questions concerning the relatedness and regional adaptability of US tea germplasm, 32 domestic individuals were evaluated using 10 InDel markers, and compared with a background population of 30 named and registered Chinese varieties of tea. The marker data were analyzed via a neighbor-joining cladistic tree derived from Nei's genetic distance, STRUCTURE, and Discriminant Analysis of Principal Components, which revealed four genetic groups. Nineteen individuals selected from the four groups were assessed for seven leaf traits, two floral descriptors, and leaf yield, to identify plants best adapted to Florida field conditions. Our analyses compared with available historical records led us to estimate the most likely provenance of some of the US individuals, to precisely identify tea plant material and to choose most diverse accessions for breeding tea improved for adaptability, yield and quality.

Population genomics of American mink using genotype data.

Understanding the genetic structure of the target population is critically important to develop an efficient genomic selection program in domestic animals. In this study, 2,973 American mink of six color types from two farms (Canadian Centre for Fur Animal Research (CCFAR), Truro, NS and Millbank Fur Farm (MFF), Rockwood, ON) were genotyped with the Affymetrix Mink 70K panel to compute their linkage disequilibrium (LD) patterns, effective population size (Ne), genetic diversity, genetic distances, and population differentiation and structure. The LD pattern represented by average r 2, decreased to <0.2 when the inter-marker interval reached larger than 350kb and 650kb for CCFAR and MFF, respectively, and suggested at least 7,700 and 4,200 single nucleotide polymorphisms (SNPs) be used to obtain adequate accuracy for genomic selection programs in CCFAR and MFF respectively. The Ne for five generations ago was estimated to be 76 and 91 respectively. Our results from genetic distance and diversity analyses showed that American mink of the various color types had a close genetic relationship and low genetic diversity, with most of the genetic variation occurring within rather than between color types. Three ancestral genetic groups was considered the most appropriate number to delineate the genetic structure of these populations. Black (in both CCFAR and MFF) and pastel color types had their own ancestral clusters, while demi, mahogany, and stardust color types were admixed with the three ancestral genetic groups. This study provided essential information to utilize the first medium-density SNP panel for American mink in their genomic studies.

Genetic Population Flows of Southeast Spain Revealed by STR Analysis

The former Kingdom of Granada, comprising the provinces of Granada, Málaga, and Almería (GMA), was once inhabited for over 700 years (711–1492 AD) by a North African population, which influenced its creation and establishment. The genetic data on 15 autosomal short tandem repeats (STRs) in 245 unrelated donor residents were examined in order to assess any possible admixture. As the two surnames in Spain follow an inheritance similar to the Y chromosome, both surnames of all 245 unrelated individuals were queried and annotated. The Spanish Statistics Office website was consulted to determine the regions with the highest frequency of individuals born bearing each surname. Further, several heraldry and lineage pages were examined to determine the historical origin of the surnames. By AMOVA and STRUCTURE analysis, the populations of the three provinces can be treated genetically as a single population. The analysis of allele frequencies and genetic distance demonstrated that the GMA population lay in the Spanish population group but was slightly more similar to the North African populations than the remainder of the Spanish populations. In addition, the surnames of most individuals originated in Northern and Central Spain, whereas most surnames had higher frequencies in Southern Spain. These results confirm that the GMA population shows no characteristics that reflect a greater genetic influence of North African people than the rest of the populations of the Iberian Peninsula. This feature is consistent with the historical data that African inhabitants were expelled or isolated during the repopulation of the region with Spaniards from Northern Spain. The knowledge of present populations and their genetic history is essential for better statistical results in kinship analyses.

Sequence-based allelic variations and frequencies for 22 autosomal STR loci in the Lebanese population

This is the first study that characterizes the sequence-based allelic variations of 22 autosomal Short Tandem Repeat (aSTR) loci in a population dataset collected from Lebanon. Genomic DNA extracts from 195 unrelated Lebanese individuals were amplified with PowerSeq 46GY System Prototype. Targeted amplicons were subjected to DNA library preparation and sequenced on the Verogen MiSeq FGx Sequencing System. Raw FASTQ data files were processed by STRait Razor v3. Sequence strings were annotated according to the considerations of the DNA Commission of the International Society for Forensic Genetics (ISFG) and tabulated herein with their respective allelic frequencies and GeneBank accession and version numbers. The sequenced Lebanese dataset resulted in 429 distinct allelic sequences as compared to the 236 alleles identified by length only. The increase in the number of alleles was observed at 18 out of 22 aSTR loci and was attributed to the sequence variations residing in both the STR repeat motifs and flanking regions. The study uncovered 25 novel aSTR allelic sequences across 12 loci for which GenBank records did not previously exist in the STRSeq BioProject, PRJNA380127. For a concordance check, the length-based allelic calls derived from the full sequences were compared to those genotyped using capillary electrophoresis (CE) methods. Population genetic parameters relevant to the evaluation of forensic DNA evidence were assessed for the sequence-based data and compared to the parameters generated from the length-based information. Using the sequence-based data, Analysis of MOlecular VAriance (AMOVA), genetic distances, and population genetic structure were evaluated for 1231 individuals sampled from the Lebanese and four U.S. populations (African American, Asian, Caucasian, and Hispanic). The results were tabulated and visualized in a population tree, multidimensional scaling scatter plots, and bar plots. This newly established sequence-based database for the Lebanese population can be beneficial for extending NGS applicability to casework or paternity testing and assessing the strength of evidence for NGS-STR profiles. The described novel sequence variants at certain loci can further help in the effort to characterize the sequence diversity of STR markers from different populations around the world.

Molecular phylogenetics and diversity of the Himalayan shrew ( Soriculus nigrescens Gray, 1842) (Eulipotyphla, Soricidae) in Southwest China

The Himalayan shrew, Soriculus nigrescens Gray, 1842, belongs to the monotypic genus Soriculus, which is distributed mainly in the Himalayan region. Previous authors have studied its classification based on morphological and molecular data. However, no comprehensive study of the diversity and phylogeny of this species has been performed. In this study, we investigated the molecularphylogeny, genetic diversity, and species divergence of S. nigrescens based on one mitochondrial gene and three nuclear genes. A total of 124 samples from 27 sites in Southwest China were analyzed. Our molecular phylogenetic analyses and species divergence reveal non-monophyly of Soriculus, potentially representing two genera and three clades. Populations from Yunnan (Clade YN) represent the subspecies S. n. minors and should recover the full species status. Populations from Himalayas (Clade A) represent the species S. nigrescens, while populations from southeastern Nyenchen Tanglha Mountains and southern Himalayas (Clade B) represent a new cryptic and unnamed species. Species delimitation analyses and deep genetic distance analysis clearly support the species status of these three evolving clades. The putative new genus and cryptic species should be studied and identified in the future using a more extensive sampling combined with a comprehensive morphological and phylogenetic analysis.

Evolutionary History and Taxonomic Reclassification of the Critically Endangered Daggernose Shark, a Species Endemic to the Western Atlantic

The family Carcharhinidae includes the most typical and recognizable sharks, although its internal classification is the subject of extensive debate. In particular, the type genus, Carcharhinus Blainville, 1816, which is also the most speciose, appears to be paraphyletic in relation to a number of morphologically distinct taxa. Isogomphodon oxyrhynchus (Valenciennes, 1839) (the daggernose shark) is a carcharinid, which is endemic to a limited area of the Western Atlantic between Trinidad and Tobago and the Gulf of Maranhão in northern Brazil, one of the smallest ranges of any New World elasmobranch species. In recent decades, I. oxyrhynchus populations have been decimated by anthropogenic impacts, which has led to the classification of the species as critically endangered by the IUCN. However, there is considerable debate on both the validity of the species (I. oxyrhynchus) and the status of Isogomphodon Gill, 1862 as a distinct entity from the genus Carcharhinus. The present study is based on a molecular assessment of the genetic validity of the I. oxyrhynchus that combines mitochondrial and nuclear markers, which were used to identify the biogeographic events responsible for the emergence and dispersal of the species in northern Brazil. The genetic distance analyses and phylogenetic trees confirmed the paraphyly of the genus Carcharhinus, recovering a clade comprising Carcharhinus+I. oxyrhynchus+Prionace glauca (Linnaeus, 1758). Our results indicate not only that the daggernose shark is actually a member of the genus Carcharhinus, but that it is genetically more closely related to Carcharhinus porosus (Ranzani, 1839) than it is to the other Carcharhinus species analyzed. Given this, I. oxyrhynchus and P. glauca are therefore reclassified and recognized as Carcharhinus oxyrhynchus and Carcharhinus glaucus. The daggernose shark, Carcharhinus oxyrhynchus, diverged from C. porosus during the Miocene, when significant geomorphological processes occurred on the northern coast of South America, in particular in relation to the configuration of the Amazon River. It is closely associated with the area of the Amazon plume, and its distinctive morphological features represent autapomorphic ecological adaptations to this unique habitat and do not reflect systematic distinction from Carcharhinus.

The complete mitochondrial genome Hainan Gymnure Neohylomys hainanensis

The Hainan Gymnure Neohylomys hainanensis is a small-size mammal which occurs in Hainan, China and north Vietnam. Here, we report the complete mitochondrial genome of N. hainanensis. The whole mitochondrial genome is 17,337 bp, and contains 13 protein-coding genes, 22 tRNAs, 2 rRNAs and one control region. The base composition of the N. hainanensis total mitogenome is: 33.4% A, 12.2% G, 33.1% T, and C 21.3%, with an A + T content of 66.5%. The K2P genetic distance analysis supports current taxonomy that places the hainanensis, sinensis and suillus in different genera. Phylogenetic analysis suggests that N. hainanensis is closely related to Neotetracus sinensis based on the complete mitochondrial genome sequences. The mitogenomic data will contribute to molecular phylogenetics and conservation genetics of the species.

Testing and using complete plastomes for authentication of medicinal Polygonatum species (Asparagaceae)

Polygonati Rhizoma, a traditional Chinese medicine important to the pharmaceutical and food industries, is frequently adulterated with morphologically similar congeneric species, posing quality and effectiveness issues for the products. Accordingly, the accurate and sensitive authentication of medicinal Polygonatum species is vital to the standardization of Polygonati Rhizoma products. In view of the difficulties in morphological analysis and the use of standard DNA barcodes for authentication of medicinal Polygonatum species, an alternative authentication method is needed. Based on inter- and intraspecies sampling, phylogenetic and genetic distance analyses were performed to evaluate the discriminative power of complete plastomes for the identification of Polygonatum species. The results indicate that the genetic criteria of complete plastomes are in good correspondence with species boundaries and therefore can be used for unambiguous identification of medicinal Polygonatum species and morphologically similar congeners, which verifies the theoretical prediction that the application of genome skimming to generate complete plastomes as molecular tags can serve as an effective and accurate method to detect whether Polygonati Rhizoma is adulterated with congeneric species. Additionally, in this study, a taxonomically well-curated and high-resolution reference plastome superbarcode library for Polygonatum was developed for the first time, providing a valuable genetic resource for the application of genome skimming to monitor and control the production and trade of Polygonati Rhizoma to guarantee the effectiveness of downstream products. The findings also provide new insights to clarify the taxonomic ambiguities of the generic circumscription of Polygonatum and Heteropolygonatum, as well as the species delimitation of Polygonatum cyrtonema, Polygonatum nodosum, and Polygonatum punctatum, which will contribute to proper exploitation and conservation of Polygonatum species.

Genetic differentiation between two subspecies of Emberiza schoeniclus and open forest bunting's evolution inferred from mitogenomes

The reed bunting, Emberiza schoeniclus (Linnaeus 1758), is the only member of the genus adapted to Mediterranean wetlands, where some subspecies are critically endangered. The first complete mitogenome of the eastern Iberian reed bunting (E. s. witherbyi) is presented here and compared with an unpublished mitogenome obtained in northeast Asia (most likely E. s. pyrrhulina). Genetic distance analyses are consistent with the new reed bunting data corresponding to two distinct lineages of E. schoeniclus. A new fossil‐calibrated phylogeny suggests that open forest buntings have suffered two rapid speciation events from Late Miocene to Pleistocene, that seem to be correlated with major climatic changes and habitat shifts. Adaptation to a new ecological niche (i.e. wetlands) could have favoured the reed bunting expansion across the Palearctic. The high intraspecific variation observed today could result from the establishment of resident populations within small areas, potentially acting as a climatic refuge.

Infraspecific genetic diversity and seed fatty acid composition in Sesamum indicum L. populations (Pedaliaceae) in Iran

Sesamum indicum L. of the Pedaliaceae family is considered an economically important oil-bearing plant that has been cultivated for more than 5000 years. In this research, we examined genetic diversity and seed fatty acid composition in 11 Iranian populations of S. indicum. We extracted the nuclear DNA using the CTAB protocol and then amplified the genomes using 10 SCoT molecular primers. For the phytochemical study, the seed fatty acid methyl esters were subjected to a GC apparatus and their composition was determined. The data were then analyzed using PAST, POPGENE, Geno-Dive, and STRUCTURE software. We determined that the percentage of polymorphic loci was 62%. According to the AMOVA test and estimated genetic diversity parameters, high genetic differentiation occurred between the examined populations, which was followed by a low rate of gene flow and Hs. Based on the Nei's genetic distance and Structure analysis, the populations were divided into seven genotype groups. Most identified genotypes had homogeneous genetic structures indicating a limited genetic flow rate. The phytochemical evaluation revealed that a great part of the seed oils was composed of unsaturated fatty acids with linoleic and oleic acids as the main compounds. We detected palmitic acid as the major saturated fatty acid. The populations were divided into four chemotype groups based on the seed oil fatty acids composition. However, the population clustering patterns in the molecular genetic and seed fatty acid analyses were not identical. These results indicated that some environmental parameters strongly affect the seed oil fatty acids composition. We suppose that the populations under study are comprised of several genotypes or cultivars grown in various Iranian locations.

Cryptic diversity in a gastrointestinal acanthocephalan of New World primates from Costa Rica

Prosthenorchis elegans is a worm of the family Archiacanthocephala that infects non-human primates in the Americas, producing an intestinal pathology that may compromise the life of its hosts. Squirrel monkeys, Saimiri oerstedii citrinellus, were found with P. elegans in Costa Rica. Histopathological analysis revealed a severe pyogranulomatous response composed by macrophages, neutrophils, eosinophils, fibroblasts and lymphocytes. Morphological worm analyses revealed 36 hooks in the proboscis distributed in six rows; and total body, hook and lemnisci length were compatible to the original descriptions of P. elegans. In addition, phylogenetic, haplotype network and genetic distance analyses were done on cytochrome oxidase subunit 1, cox1, sequences obtained from the collected specimens. Sequences obtained herein clustered separately with high posterior probabilities in a Bayesian Inference tree and showed 8.12% nucleotide differences when compared to P. elegans from Colombia. This high divergence was confirmed in the TCS network that separated Colombian and Costa Rican sequences by 32 mutational steps, a genetic distance PCA which separated sequences from both geographical locations by 89.5% and an FST value of 0.655, indicating the presence of cryptic diversity in P. elegans. Additional studies from specimens collected from other definitive hosts and geographical locations are required to better understand the biodiversity of this species.

GENETIC DIVERSITY OF IRAQI LOCAL GOAT BREEDS BY RAPD DNA MARKERS

Genetic diversity of three Iraqi local goat breeds (Black, Hybrid, and Meriz) was studied by using random amplified polymorphic DNA (RAPD) markers. Fifteen primers were used, they generated a total of 259 amplification products, from which 142 bands were polymorphic, revealing 55.29% polymorphism. It was found that the mean value of Nei’s gene diversity (h) and Shannon's ınformation index (I) were 0.1778 and 0.2546, respectively. According to the analysis of genetic distances among breeds, the highest genetic distance recorded between Black and Hybrid 0.5108, while the lowest genetic distance recorded between Hybrid and Meriz 0.1431. The phylogenetic dendrogram based on Nei’s genetic distance analysis was in agreement with their phenotypic similarities in which the tree separated the surveyed breeds into two clusters, the first one including Black goat breed, and the second cluster includes Hybrid and Meriz breeds. These results indicated that Black goat breed is most genetically distant from both Hybrid and Meriz breeds. Finally, the moderate value for both of polymorphism and genetic diversity which obtained from the present study indicate that these breeds are genetically different, which provide a good background about these breeds for genetic improvement and conservation of our local goat breeds in the future.

Morphological Description and Molecular Analysis of Newly Recorded Asteroid, Henricia djakonovi Chichvarkhin, 2017 (Asteroidea: Spinulosida: Echinasteridae), from Dokdo Island, Korea

We recently collected the samples of Henricia from adjacent waters of Dokdo Island, Korea, using trimix SCUBA diving. Based on a combined result of morphological and molecular analysis, we identified our specimen as Henricia djakonovi Chichvarkhin, 2017, which is newly recorded in Korea. Morphologically, H. djakonovi has crescent abactinal plates bearing numerous pillar-shaped abactinal spines with a droplet-like apical tip. Moreover, molecular analysis based on the mitochondrial COI gene occurred that clearly distinguished H. djakonovi from other species of Henricia in the pairwise genetic distance and maximum likelihood analysis. Accordingly, 15 species of Henricia are recorded in Korean fauna, including H. djakonovi.

Genetic polymorphism and forensic efficiency of 21 autosomal STR loci from Shandong Han population in Northern China

Background Highly polymorphic autosomal STR loci are useful for understanding population structure better and for forensic application, however the non-CODIS STR loci in the Han population of Shandong, located in Northern China, are not well-characterised. Aim To investigate population genetic polymorphism and forensic efficiency of 21 autosomal STR loci from the Shandong Han population in Northern China and reveal the genetic relationships with other populations both at home and abroad. Subjects and methods In this study, population genetic data of 21 autosomal STR loci included in the Goldeneye DNA ID 22NC Kit that includes four CODIS loci and 17 non-CODIS loci were determined for 523 unrelated Han individuals in Shandong. Results Significant deviations from Hardy–Weinberg equilibrium were not observed. A total of 233 alleles were detected with allele frequencies ranging from 0.0010 to 0.3728. The combined power of discrimination was 0.99999999999999999999999990011134, and the combined power of exclusion was 0.99999999788131. Furthermore, in an analysis of population differentiation Nei’s standard genetic distance and multidimensional scaling analysis, which were conducted based on the overlapping 15 STR loci, revealed that the Shandong Han population was most closely related to populations in close geographic proximity. Conclusions This study demonstrated that the 21 autosomal STR loci included in the GoldeneyeTM DNA ID 22NC system are highly polymorphic and suitable for forensic identification and paternity testing in the Shandong Han population. Additionally, the present results enrich the population genetic database.

A new species of Loricaria (Loricariidae: Loricariinae) from the upper Amazon River basin, Colombia

Abstract A new species of Loricaria is described from the upper Amazon River basin, Colombia. The new species is distinguished from its congeners primarily by having the dorsal portion of head with uniform black or dark brown coloration extending to three or four plates posterior to dorsal fin base, or with two longitudinal bands from tip of the snout to origin of dorsal fin; abdominal plates tightly joined and completely covering the median abdominal space and pectoral girdle; and pectoral and dorsal fins totally black or dark brown, without bands, spots, or blotches. The new species is further distinguished by plate counts, and body measurements. An analysis of genetic distances using the cytochrome oxidase c subunit 1 marker of the mitochondrial genome showed a clear differentiation between the new species and Loricaria cataphracta (5.8–7.6%), L. nickeriensis (5.7–6.1%), and L. simillima (2.7–7.0%). Species delimitation analyses were carried out, which further supported the new species as a divergent lineage within the genus. Fish species diversity of the upper Amazon River basin and taxonomic issues related to L. simillima are included as part of the discussion.

The genetic relationship of Vietnamese gaurs assessed by mtDNA sequences

This study aimed to assess the genetic relationship of Vietnamese gaurs from Central Highland and other gaurs from the Southeast Asia and India. The results showed that 15 polymorphic sites were found in 16S sequences between these gaurs. Vietnamese gaurs exhibited 15 identical SNPs with Cambodian gaur, while exposed 7 identical SNPs to Malayan gaur. The genetic distance analysis demonstrated that Vietnamese gaur showed the lowest distance to Bos frontalis (0.0086±0.0022) and Bos gaurus (0.0182±0.0054). Phylogenetic tree analysis indicated 3 groups of gaurs. Vietnamese gaur located in clade III which concluded Bos gaurus, Bos javanicus, Bos frontalis.

Microssatellite markers for plant variety protection of clonally propagated forest trees: a case study in teak (Tectona grandis L.f.)

Abstract Forest trees cultivars developed by breeders have been increasingly deployed as clones, following long generations of breeding and testing. An established protocol for distinctiveness, uniformity and stability (DUS) testing becomes an essential element for protecting the intellectual property rights associated with these clones. DUS testing with morphological descriptors has, however, shown limitations in categorically distinguishing cultivars, especially with narrow genetic base. DNA fingerprinting based on microsatellite markers has been a powerful tool to discriminate clones. Teak (Tectona grandis) is an economically valuable exotic timber species planted in Brazil. We assessed the individual and combined performance of a selected set of 21 teak microsatellites for identity analysis and parentage testing in a sample of 50 clones planted in Brazil. The clones displayed high genetic diversity attributable to their wide provenance origin. The 21 microsatellites combined provide high power of individual identification with a combined probability of identity of 1.84E-23 for unrelated individuals, and 4.82E-09 for full-sibs, and a power of paternity exclusion higher than 99.99999 % in all testing scenarios. Variable subsets of these 21 markers still provide abundant power of discrimination, although a recommended set should include a minimum of 12 markers with higher information content and reliable genotyping performance. Relatedness and genetic distance analyses revealed unexpected identities or significant recent shared ancestry among otherwise considered unique clones. These results advocate for the importance of including DNA markers, at least as discretionary complementary descriptors to the 22 morphological traits currently adopted for plant variety protection of teak cultivars in Brazil.

Urban population structure and dispersal of an Australian mosquito (Aedes notoscriptus) involved in disease transmission

Dispersal is a critical parameter for successful pest control measures as it determines the rate of movement across target control areas and influences the risk of human exposure. We used a fine-scale spatial population genomic approach to investigate the dispersal ecology and population structure of Aedes notoscriptus, an important disease transmitting mosquito at the Mornington Peninsula, Australia. We sampled and reared Ae. notoscriptus eggs at two time points from 170 traps up to 5 km apart and generated genomic data from 240 individuals. We also produced a draft genome assembly from a laboratory colony established from mosquitoes sampled near the study area. We found low genetic structure (Fst) and high coancestry throughout the study region. Using genetic data to identify close kin dyads, we found that mosquitoes had moved distances of >1 km within a generation, which is further than previously recorded. A spatial autocorrelation analysis of genetic distances indicated genetic similarity at >1 km separation, a tenfold higher distance than for a comparable population of Ae. aegypti, from Cairns, Australia. These findings point to high mobility of Ae. notoscriptus, highlighting challenges of localised intervention strategies. Further sampling within the same area 6 and 12 months after initial sampling showed that egg-counts were relatively consistent across time, and that spatial variation in egg-counts covaried with spatial variation in Wright’s neighbourhood size (NS). As NS increases linearly with population density, egg-counts may be useful for estimating relative density in Ae. notoscriptus. The results highlight the importance of acquiring species-specific data when planning control measures.

Effect of selective logging on the genetic differentiation of Juglans pyriformis Liebm. populations

Juglans pyriformis Liebm. (Juglandaceae) is a threatened and endemic tree that grows in the cloud forest of Mexico. Natural populations of this species have been reduced due to, among others, changes in land use, overexploitation, and logging, with probable effects on its genetic diversity and structure. To determine the levels of variation and genetic structure of two populations with different silvicultural regimes, six inter-simple sequence repeat (ISSR) primers were used to amplify DNA from 35 individuals from a high-logging population and 32 from a low-logging population. The results show a higher polymorphism in the low-logging population (81.5%) compared to the high-logging population (77.4%). The genetic differentiation coefficient (PhiPT) values (0.109), genetic distance (0.134) and STRUCTURE analysis (Fst = 0.2271, P = 0.04) show significant genetic differentiation between populations. Rare, private, and monomorphic bands were detected in both populations. These results confirm the trend of reduced genetic variation due to logging.