Knowledge Of Genetic Diversity Research Articles

Genomic Diversity and Demographic History of the Endangered Sichuan hill-partridge (Arborophila rufipectus).

Species conservation can be improved by knowledge of genetic diversity and demographic history. The Sichuan hill-partridge (Arborophila rufipectus, SP) is an endangered species endemic to the mountains in southwestern China. However, little is known about this species' genomic variation and demographic history. Here, we present a comprehensive whole-genome analysis of six SP individuals from the Laojunshan National Nature Reserve in Sichuan Province, China. We observe a relatively high genetic diversity and low level of recent inbreeding in the studied SP individuals. This suggests that the current population carries genetic variability that may benefit the long-term survival of this species, and that the present population may be larger than currently recognized. Analyses of demographic history showed that fluctuations in the effective population size of SP are inconsistent with changes of the historical climate. Strikingly, evidence from demographic modeling suggests SPs population decreased dramatically 15,100 years ago after the Last Glacial Maximum (LGM), possibly due to refugial isolation and later human interference. These results provide the first detailed and comprehensive genomic insights into genetic diversity, genomic inbreeding levels, and demographic history of the Sichuan hill-partridge, which are crucial for the conservation and management of this endangered species.

Current progress and future prospects for understanding genetic diversity of seed plants in China

AbstractGenetic diversity represents the fundamental basis of biological variation within species, and is therefore the ultimate representation of biodiversity. Despite that all forms of diversity being defined by genomic differences, genetic diversity has received relatively less attention compared with species and ecosystem diversity. Here, we review recent literature and conclude that progress in understanding genetic diversity of seed plants is strongly associated with advances in sequencing technology. We here present case studies to illustrate the application of genetic diversity for tracing crop domestication and delimiting species boundaries. Understanding genetic diversity is particularly critical for the field of conservation biology, and there is a clear shift to population‐level genetic studies to understand rare species. We then document additional factors that potentially influence genetic diversity, including climate change, habitat fragmentation, and species invasion. Finally, we identify current research limitations and propose directions for future studies. We highlight the need to develop broad‐scale genetic diversity knowledge, combined with other aspects of diversity to improve biodiversity conservation outcomes. We conclude that populating global databases with genomic‐scale sequence data for all species is an urgent and achievable goal now.

Assessing the Genetic Diversity of Parents for Developing Hybrids Through Morphological and Molecular Markers in Rice (Oryza sativa L.)

The advancement of hybrid technology plays a crucial role in addressing yield plateau and diminishing resources in rice cultivating regions. The knowledge of genetic diversity among parental lines is a prerequisite for effective hybrid breeding program. In the current study, a set of 66 parental lines was studied for diversity based on both morphological characters and microsatellite SSR markers. The genetic variability parameters unveiled that number of productive tillers per plant, single plant yield and hundred grain weight exhibited additive gene action. Mahalanobis D2 statistics grouped the genotypes into ten clusters based on yield and grain traits. The principal component analysis identified four PCs with eigen value more than one accounting for 71.28% of cumulative variance. The polymorphic SSR markers produced 122 alleles among which the marker RM474 recorded the highest values for Polymorphic Information Content (0.83) and heterozygosity index (0.85). The genotypes were assembled in seven clusters based on jaccard distances using the Unweighted Pair Group method with Arithmetic Mean (UPGMA). The population structure divided the entire population into 3 subpopulations. In both clustering, there was difference in the assembling of genotypes, but, good performing genotypes identified through PCA were positioned in different clusters in both approaches. The genotypes CBSN 495 and CBSN 494 located in different clusters were identified as the potential restorers for high yielding and short duration hybrids. The hybridization among CRR Dhan 310, CRR Dhan 315, IR64 DRT, CB 17135 and WGL 347 can be performed to develop climate smart varieties with improved nutrition.

The weak genetic structure of Melolontha melolontha (L.) and Melolontha hippocastani (Fabr.), two important forest pests, indicates their large population sizes and effective gene flow

Abstract Cockchafers Melolontha spp. are polyphagous root pests and outbreak species of considerable economic importance to forestry in Europe. Knowledge of genetic diversity within and between cockchafer populations is largely unexplored but could lead to more effective monitoring and management strategies of these pests. In this study, we fill several gaps in the knowledge of the genetic population structure of Melolontha melolontha and Melolontha hippocastani. Using microsatellite loci and over 200 individuals per species, we examined the genetic structure of Melolontha spp. populations collected from three primary outbreak areas in central and southeastern Poland. We demonstrated that our focal species share some common genetic patterns, such as considerable genetic diversity within subpopulations (within sampling sites) with minor effects of past bottlenecks possibly masked by current population sizes. The estimates of effective population sizes, although subject to wide credibility intervals, indicated a large number of individuals contributing to further generations of the population. The migration rates exceed the threshold of one per generation required for gene flow and maintenance of population equilibrium, indicating limited impact from forest management practices on either cockchafer species. While genetic differentiation was observed in M. melolontha populations, supported by various indices (fixation index, principal coordinate analysis, assignment tests), the M. hippocastani populations were genetically similar. This disparity may hint at the potential historical divergence between these species. In this aspect, more detailed phylogeographic and population genetic studies covering a large area of the Palaearctic distributions of both species are required. Our findings constitute one of the initial efforts aimed at delineating the genetic diversity, differentiation, population structure, gene flow, and migration patterns within Melolontha spp. This exploration is especially significant for M. hippocastani, given its completely unexplored genetic population structure.

Population structure and history of North Atlantic Blue whales (Balaenoptera musculus musculus) inferred from whole genome sequence analysis

Knowledge of genetic diversity and structure is essential for developing conservation strategies for endangered species. Blue whales were hunted to near extinction in the mid-twentieth century. Not-withstanding almost 380,000 animals killed globally, much remains unknown about their population structure and migration patterns. Herein, we use whole genome sequencing to elucidate the poorly understood population genetics of North Atlantic (NA) blue whales. We generated a de novo genome assembly for a NA blue whale to analyze 19 other whole genomic sequences and 31 complete mitochondrial genomes. Present-day and historical samples (earliest from 1876) from the Atlantic and Antarctic Oceans were included to understand the impact of whaling on the genetic diversity of this species. We found low but statistically significant population structuring and high genetic diversity. Demographic modeling using fastsimcoal2 rejected an absence of gene flow between eastern and western NA blue whales and suggested an asymmetric west to east gene flow. Introgression estimated using D-statistics between blue and fin whales (Balaenoptera physalus), was observed in all present-day samples. This gene flow was found to be unidirectional from fin whales to blue whales and accounts for ~ 3.5% of the NA blue whale’s genome. Our sequencing and population structure analyses provide a genomic baseline to inform ongoing conservation strategies for this iconic species.

Genetic diversity and population structure of Saccharum hybrids.

Sugarcane breeding programs incorporate foreign material to broaden the genetic base, expanding the gene pool. In South America, the Inter-university Network for the Development of the Sugarcane Industry (RIDESA) and Estación Experimental Agroindustrial Obispo Colombres (EEAOC) sugarcane breeding programs from Brazil and Argentina, respectively, have never exchanged materials. In that sense, the knowledge of the genetic diversity and population structure among sugarcane genotypes of both germplasm banks, determined in a reliable way through their molecular profiles, will provide valuable information to select the best parental accessions for crossing aimed at the efficient introgression of desirable alleles. For that, the aim was to determine the genetic diversity and population structure of 96 Saccharum commercial hybrids from RIDESA and EEAOC sugarcane breeding programs by using TRAP, SSR and markers related to disease resistance (e.g. Bru1 and G1). Genetic structure was determined through genetic similarity analysis, analysis of molecular variance (AMOVA), Multidimensional scaling (MDS), and a Bayesian method. Average PIC values were 0.25 and 0.26, Ho values were 0.24 and 0.28, and He values were 0.25 and 0.28, for TRAP and SSR primers, respectively. Genetic similarity, MDS, and analysis of structure revealed that Brazilian and Argentinean genotypes clustered in two groups clearly differentiated, whereas AMOVA suggested that there is more variability within programs than between them. Regarding Bru1 markers, Brazilian genotypes showed high frequency of haplotype 1 (71.4%) whereas Argentinean genotypes showed high frequency of haplotype 4 (80.8%); haplotypes 1 and 4 are indicated for the presence and absence of the brown rust resistance gene (Bru1), respectively. Respecting the G1 marker, most of the evaluated genotypes (60.4%) showed the presence of the fragment, in a similar proportion for genotypes of both programs. In conclusion, the exchange of materials, at least the most diverse genotypes, between RIDESA and EEAOC breeding programs will allow extending the genetic base of their germplasm banks, and the knowledge of genetic diversity will help breeders to better manage crosses, increasing the probability of obtaining more productive varieties.

Morpho-Molecular Genetic Diversity Analysis of Little Millet (Panicum sumatrense) using Yield Attributing Traits and ISSR Markers to Evaluate its Performance as a Summer Crop

The knowledge of genetic diversity among the genotypes and its relationship plays a vital role for genetic improvement in crop breeding programs. The present study was conducted to assess the performance of 18 little millet genotypes in local conditions of Bihar and analyze the genetic diversity by using morphological traits and 16 ISSR markers. The field experiment was conducted in RBD design in the month of April 2020, to evaluate the performance of the plant as a summer crop. ANOVA analysis revealed the presence of substantial amount of variability among 18 genotypes. The maximum mean sum of square values was recorded for plant height followed by flag leaf length within the genotypes. The descriptive statistical analysis showed that plant height followed by length of flag leaf contributed the most towards the divergence. A total of 117 alleles including 43 unique alleles and 74 shared alleles were obtained by amplification with ISSR primers. All the primers were highly polymorphic and produced amplified product with a size ranged between 354-2315 bp. The primers UBC 807 followed by HB 10 and UBC 814 were found to be the most effective in detecting genetic diversity. The dendrogram based on Dice’s similarities coefficient, grouped the genotypes into five clusters. The genotypes WV-168 and WV-115 followed by WV-122 and WV-124 were found to have greatest variability. The present study identified genotypes which can be grown as summer crops. The diversified genotypes among the population were also identified, which could be utilized as parents for breeding program.

Assessment of Morphological Variations and Crop Performance among Commonly Cultivated Bambara Groundnut (Vigna subterranea (L) Verdc.) Landraces in Gombe, Nigeria

Bambara groundnut is cultivated by low-income earning farmers at the subsistence level without knowledge of genetic diversity on major morphological and yield traits. This study aimed to assess morphological variations and crop performance among commonly cultivated Bambara groundnut landraces. The five most commonly cultivated Bambara groundnut landraces were collected from farmers and were planted randomly in a complete block design (RCBD) with three replications in the Botanical Garden of Gombe State University. The results of the analysis of variance from this study revealed significant variation among some of the traits. The results on germination percentage showed that the landraces germinated between seven to ten (7-10) days after planting with 73% and 100% as the lowest and highest mean percentages. The highest mean number of leaves observed was in Stripped Black 122 whereas the lowest mean was 52. The highest mean observed at ten weeks after planting was 31.20 and the lowest mean was 23.00 in stripped brown and stripped black landraces. The highest mean plant canopy spread observed was 70cm in the white landrace, whereas the lowest mean plant canopy observed was 35cm in the black landrace. The highest mean biomass fresh weight observed was 214.95 among the white landrace while the lowest mean observed was 80.30 among the red landrace. A similar trend was recorded on biomass dry weight where the white landrace recorded 101.23 while the red landrace recorded the lowest mean biomass dry weight at 30.62 these traits have highlighted the significance chosen various parameters in selection for breeding and improvement of Bambara groundnut.

Detection of Genetic Patterns in Endangered Marine Species Is Affected by Small Sample Sizes.

Simple SummaryKnowledge of genetic diversity is crucial to improve conservation plans for endangered species and ensure their long-term persistence. However, it may be difficult to accurately estimate genetic diversity when it is unfeasible to obtain sufficiently large sample sizes, which is often the case for marine endangered species. Here, we use Patella ferruginea as a model to investigate how small sample sizes affect genetic diversity estimates. We show that small sample sizes do not always hamper the detection of genetic patterns in endangered marine species, even though caution is needed when genetic divergence among populations is weak.Knowledge of Genetic diversity and its spatial distribution is crucial to improve conservation plans for endangered species. Genetic tools help ensure species’ long-term persistence by unraveling connectivity patterns and evolutionary trajectories of populations. Here, microsatellite genotypes of individuals from populations of Patella ferruginea are used to assess the effect of sample size on metrics of within-and between-population genetic diversity by combining empirical and simulated data. Within-population metrics are slightly to moderately affected by small sample size, albeit the magnitude of the bias is proportional to the effective population size and gene flow. The power of detecting genetic differentiation among populations increases with sample size, albeit the gain of increasing the number of sampled individuals tends to be negligible between 30 and 50. Our results line up with those of previous studies and highlight that small sample sizes are not always a hindrance to investigating genetic patterns in endangered marine species. Caution is needed in interpreting genetic patterns based on small sample sizes when the observed genetic differentiation is weak. This study also highlights the importance of carrying out genetic monitoring in seemingly well-preserved but potentially isolated populations.

Simple Sequence Repeats-Based Genetic Characterization and Varietal Identification of Potato Varieties Grown in Pakistan

The potato (Solanum tuberosum L.) is an important cash crop with a complex genome and with features of aneuploidy with a high level of heterozygosity. It is a prerequisite for potato breeding to have knowledge of genetic diversity and population structure. To understand the genetic characteristics of potato cultivars in Pakistan, 25 potato varieties were characterized with simple sequence repeat (SSR) markers to distinguish closely related varieties. In total, 214 alleles were amplified with 35 SSR markers exhibiting 89.2% polymorphism. The maximum number of alleles and polymorphic alleles per locus were 20 and 14 for the markers S25 and S174, respectively. The polymorphic information content (PIC) extended from 0.00–0.87. The size of the amplified PCR product ranged between (30–1000 bp). A cluster analysis divided the 25 varieties into three clusters: cluster I revealed the most diversity, followed by cluster II with 11 varieties and cluster III with 13 varieties. Nei’s genetic diversity and minimum spanning network (MSN) depicted the Mozika variety as the most diverse compared to the rest of the varieties. Nei’s coefficient was found to vary from 0.53 to 0.95. Out of the 25 studied varieties, 16 were uniquely identified by 29 polymorphic SSR bands of different sizes with a maximum size amplified by S4026/4027 (800bp) and a minimum by S170 (90bp). The genetic diversity and varietal identification determined in the present study has molecular and breeding-related significance with respect to the utilization and protection of intellectual property rights of potato cultivars for sustainable potato production in Pakistan.

Phenotypic Diversity Analysis of Lens culinaris Medik. Accessions for Selection of Superior Genotypes

Knowledge of genetic diversity in lentil is imperative for selection of parental genotypes that could yield heterotic combinations. The aim of the present study was to investigate the genetic diversity among 43 diverse lentil genotypes to identify complementary and unique genotypes for breeding programmes. Field experimentation was carried out in two winter seasons (2019–2020 and 2020–2021) in Hisar (29°10′ N, 75°46′ E) using randomized block design (RBD) with three replications. The chi-square test analysis showed significant genotypic variation for qualitative traits. There was substantial genetic variation among the genotypes for most quantitative traits, connoting the need to exploit a high degree of genetic variation through selection. Multiple-trait selection would also be beneficial, as seed yield was positively associated with most quantitative traits. The principal component analysis recognized seed yield (SY), days to 50% flowering (DTF), days to maturity (DTM), number of pods per plant (NPP), number of primary branches (NPB), plant height (PH) and biological yield (BY) as target traits that prominently described variation within lentil genotypes. The cluster analysis discriminated the lentil genotypes into five discrete clusters. Cluster III and V were the most distant groups, implying wider diversity among the genotypes of these groups. Furthermore, cluster analysis identified genotypes IPL 316, LH 17-19, LH 18-04, LH 17-17, IPL 81 and Pant L-8 as high-yielding genotypes, while L 4717 was identified as an early-maturing genotype. Therefore, to obtain a broad spectrum of early-maturing high-yielding segregants, the selected genotypes may serve as superior parental lines for structuring breeding strategies.

SELECTION OF SUPERIOR GENOTYPES OF LIMA BEAN LANDRACES BY MULTIVARIATE APPROACH

ABSTRACT The knowledge of genetic diversity in plant population is essential to the success of plant breeding programs. Thus, previous characterization of landraces is one of the first steps before the indication of genotypes to these plant breeding programs. This study aimed to characterize, through morphological traits, and estimate the genetic diversity in landraces of lima bean (Phaseolus lunatus L.). Genetic diversity was estimated by using multivariate methods that selected individual landraces to be indicated for farmers and consumers. According to morphological traits proposed by Biodiversity International, the genotypes UFPI-667 and UFPI- 682 showed higher dissimilarity and high potential to be used in crosses since they are genetically distant and complementary. The principal component analysis identified positive and significant phenotypic associations between variables: pod length, pod width, and grain production. According to the multivariate methods used, the landraces UFPI-666, UFPI-650, UFPI-651, UFPI-687, UFPI-658, UFPI-673, UFPI-667, and UFPI-674 are potential candidates for selection since they have relevant features for lima bean breeding, such as shorter cycles and higher grain production. This study showed that multivariate analysis can be used as an effective tool to find potential traits in lima bean and can assist the lima bean breeders in the selection of potential landraces. Accessions UFPI-667 and UFPI-682 can be indicated as genitors for breeding programs, as they are genetically distant and complementary in their characteristics.

Germplasm, conservation and its potential role in crop improvement

Genetic resources supply the basic mechanics that allow plants to convert soil, water, and sunlight into something useful for human consumption. One of the most sustainable approaches for conserving precious genetic resources in the long run is to use plant genetic resources in crop development, followed by adoption, cultivation, and consumption or marketing of improved cultivars by farmers. This review's goal is to describe the challenges surrounding the use of genetic resources in crop development. Crop genetic resources are the foundation of agricultural output, and their conservation and application have yielded major economic benefits. However, because crop genetic resources are essentially public assets, private incentives for conservation of genetic resources may fall short of meeting public goals. To effectively harness the existing resources in further valuable ways, a significantly greater characterization and knowledge of genetic diversity and its distribution is required. It's critical to plan collecting excursions and conservation operations efficiently. The value of diversity lies in its application. The most basic method of conservation is to combine multiple ex situ and in situ conservation strategies in a complimentary manner. Biotechnology provides us with a new set of tools for studying genetic resources, as well as conservation measures. The utilization of distantly related trait carriers as donors for the desired traits has become more possible thanks to gene technology. Given the restricted national plant breeding capacity, international germplasm exchanges will continue to be vital in influencing new climatic and climate conditions.

Reprint: Investigation of Genetic Divergence in Local Sunflower Hybrids and Inbred Lines by Applying Morphological Markers

Knowledge of genetic diversity is the basic requisite for any plant breeding program. Seventeen sunflower hybrids and fifteen inbred lines including ten Cytoplasm male sterile lines and five restorer lines were evaluated at the experimental area of National Agriculture Research centre, Islamabad, Pakistan during autumn-2011. The objective of study was to investigate the genetic diversity, categorize the proficient cross combiners and approximate characters association among sunflower hybrids and inbred lines. Data was estimated on i.e. flower initiation days, full flowering days, full developmental days, height of plant, disk diameter, stem thickness, leaves per plant, hundred achenes weight, achenes yield and oil content percentage. The maximum achenes yield was contributed by Hysun-33 2119 kg ha-1. Followed by SMH-0924 and SMH-0925, SMH-1028 and SMH-0926 were suggested as potential significant hybrids for future breeding plans to incorporate maximum achenes yield and oil content percentage. The CMS-11, CMS-25 and CMS-10 were long statured with vigorous stem and all the restorers were early maturing recommended for including in hybridization program to generate high heterotic factions. Cluster diagram based on Euclidean dissimilarity matrix grouped hybrids as well as inbred lines in four groups. The group I and IV consist of four whereas group II and group III have three and five hybrids respectively. All the restores were clustered in III and IV and CMS in I and II groups respectively. According to principle component analysis the first two components contribute 64% and 89% in total variation in hybrids as well as in inbred lines respectively.

Contribution to a reference library of DNA barcodes of Colombian freshwater fishes.

BackgroundThe Barcode of Life initiative was originally motivated by the large number of species, taxonomic difficulties and the limited number of expert taxonomists. Colombia has 1,610 freshwater fish species and comprises the second largest diversity of this group in the world. As genetic information continues to be limited, we constructed a reference collection of DNA sequences of Colombian freshwater fishes deposited in the Ichthyology Collection of the University of Antioquia (CIUA), thus joining the multiple efforts that have been made in the country to contribute to the knowledge of genetic diversity in order to strengthen the inventories of biological collections and facilitate the solution of taxonomic issues in the future.New informationThis study contributes to the knowledge on the DNA barcodes and occurrence records of 96 species of Colombian freshwater fishes. Fifty-seven of the species represented in this dataset were already available in the Barcode Of Life Data System (BOLD System), while 39 correspond to new species to the BOLD System. Forty-nine specimens were collected in the Atrato River Basin and 708 in the Magdalena-Cauca asin during the period 2010-2020. Two species (Loricariichthysbrunneus (Hancock, 1828) and Poeciliasphenops Valenciennes, 1846) are considered exotic to the Atrato, Cauca and Magdalena Basins and four species (Oncorhynchusmykiss (Walbaum, 1792), Oreochromisniloticus (Linnaeus, 1758), Parachromisfriedrichsthalii (Heckel, 1840) and Xiphophorushelleri Heckel, 1848) are exotic to the Colombian hydrogeographic regions. All specimens are deposited in CIUA and have their DNA barcodes made publicly available in the BOLD online database. The geographical distribution dataset can be freely accessed through the Global Biodiversity Information Facility (GBIF).

GENETIC DIVERGENCE AND CLUSTER ANALYSIS FOR YIELD ATTRIBUTING TRAITS IN ELITE LINES OF CHILLI

The genetic diversity of thirty chiili elite lines was estimated using Mahalanobis D2 and 12 yield attributing traits. ANOVA found that there was a significant degree of variation among elite lines. Because hybrids between lines of various clusters serve a vital role in choosing possible parents and assessing the degree of divergence in the chilli elite lines, genetic diversity knowledge is crucial in plant breeding. Fruit yield/plant (45.52) contributed the most (45.52 percent) to overall genetic difference, followed by fruit width (16.09). It also displayed lines that were divided into six groups. Clusters IV and V had the greatest intercluster distance, admitted lines from a diverse gene pool, and as per cluster mean analysis, these clusters contained high values for most of the yield attributing traits such as plant height, plant spread, fruit width, days of flower initiation, days of 50% flowering, and canopy temperature. The lines in these clusters act as superior segregants for yield traits and are 2020/CHIVAR-2, 2020/CHIVAR-3, K2, 2020/CHIVAR-5, 2020/ CHIVAR-7, 2020/CHIVAR-8, 2020/CHIVAR-9, 2018 CHIHYB 03, KASHI GAURAV, KASHI ANMOL.

Insights Into the Genetic Diversity of Nordic Red Clover (Trifolium pratense) Revealed by SeqSNP-Based Genic Markers.

Red clover (Trifolium pratense) is one of the most important fodder crops worldwide. The knowledge of genetic diversity among red clover populations, however, is under development. This study provides insights into its genetic diversity, using single nucleotide polymorphism (SNP) markers to define population structure in wild and cultivated red clover. Twenty-nine accessions representing the genetic resources available at NordGen (the Nordic gene bank) and Lantmännen (a Swedish agricultural company with a red clover breeding program) were used for this study. Genotyping was performed via SeqSNP, a targeted genotype by sequencing method that offers the capability to target specific SNP loci and enables de novo discovery of new SNPs. The SNPs were identified through a SNP mining approach based on coding sequences of red clover genes known for their involvement in development and stress responses. After filtering the genotypic data using various criteria, 623 bi-allelic SNPs, including 327 originally targeted and 296 de novo discovered SNPs were used for population genetics analyses. Seventy-one of the SNP loci were under selection considering both Hardy-Weinberg equilibrium and pairwise FST distributions. The average observed heterozygosity (HO), within population diversity (HS) and overall diversity (HT) were 0.22, 0.21 and 0.22, respectively. The tetraploids had higher average HO (0.35) than diploids (0.21). The analysis of molecular variance (AMOVA) showed low but significant variation among accessions (5.4%; P < 0.001), and among diploids and tetraploids (1.08%; P = 0.02). This study revealed a low mean inbreeding coefficient (FIS = −0.04) exhibiting the strict outcrossing nature of red clover. As per cluster, principal coordinate and discriminant analyses, most wild populations were grouped together and were clearly differentiated from the cultivated types. The cultivated types of red clover had a similar level of genetic diversity, suggesting that modern red clover breeding programs did not negatively affect genetic diversity or population structure. Hence, the breeding material used by Lantmännen represents the major genetic resources in Scandinavia. This knowledge of how different types of red clover accessions relate to each other and the level of outcrossing and heterozygosity will be useful for future red clover breeding.

Genetic diversity of Betula nana in Sweden and conservation implications for protection of relict Polish populations

Abstract The natural range of the dwarf birch (Betula nana L.) includes the boreal, subarctic and arctic regions of Europe, Asia and North America, where it is relatively common. In Poland, it is a relict species occurring in fragmented populations. Using the random amplification of polymorphic DNA (RAPD) technique, we investigated the genetic diversity of the four Swedish populations representing a part of the continuous range of dwarf birch. With the knowledge of the level of genetic diversity of a population from a continuous distribution, we can assess the genetic status of polish populations and answer the question if habitat fragmentation and a decrease in population size lead to a loss in genetic diversity. Knowledge of genetic diversity is important for species conservation, especially to predict their ability to respond to environmental pressures. We found that the populations Abisko, Malbo, Gällivare and Storlien, which are located at the edge of the natural range of B. nana and occupy different habitats, are genetically diverse to varying degrees. The northern populations from Abisko and Gällivare showed a lower level of genetic polymorphism than the population from Malbo, the southernmost site of dwarf birch in Sweden. The data presented indicate higher genetic diversity existed within populations, whereas genetic differentiation between populations was lower. The high level of genetic differentiation within B. nana populations that were analysed in the present study may be explained by a limited capacity for dispersal among populations via both pollen and seeds. We found that the level of genetic diversity in one of the Polish populations of B. nana is comparable to that in areas in Scandinavia where populations are large and continuous. Based on these studies, we conclude that the “Linje” population has sufficient genetic resources.

Molecular characterization of the spectacled caiman (Caiman crocodilus) in the upper Magdalena River basin, Colombia: Demographic and phylogeographic insights

Maintenance of high levels of genetic diversity is crucial for the recovery of overexploited species and gaining knowledge of genetic diversity of natural populations is crucial to define effective conservation strategies. Spectacled caimans (Caiman crocodilus) were unsustainably exploited for decades in Colombia causing drastic population reductions with unknown effects on genetic structure. We molecularly characterized three spectacled caiman populations from the upper Magdalena River basin (UMRB), analyzing them within the context of the trans-Andean C. c. fuscus sensu stricto lineage, assessing nucleotide and genetic diversity, demographic history, and phylogeography at different scales. Seventeen of the 23 mitochondrial haplotypes currently described for Colombia are present in the UMRB, showing high levels of genetic diversity even when compared with the trans-Andean region (uncorrected genetic distances 0.00-0.87%). Mutational steps between closest haplotypes ranged from one to four while the most differentiated haplotypes were separated by 19 mutational steps across the whole trans-Andean region. Distribution of pairwise nucleotide differences and raggedness tests showed unimodal patterns of mismatch distribution curves fitting the sudden expansion model. Average time since demographic expansion for UMRB, Colombia, and trans-Andean region were inferred as 10,540, 7,591, and 7,071 years before present, respectively, placing the latest expansion close to the Pleistocene-Holocene boundary. Intriguingly, samples from Tolima were overall more related to those collected from Panama and Costa Rica (0.34 ± 0.15%) than the ones collected across Choco (0.45 ± 0.15%), Cauca (0.70 ± 0.09%), and Nariño (0.60 ± 0.14%) departments. We discuss our genetic findings in the context of the management policies carried out in the country during the last decades (unsustainable and sustainable use, and population restocking), evaluating the implications of these events for the genetic integrity and conservation of the species.

Assessment of the Genetic Diversity of Some Female Jojoba (Simmondsia chinensis (Link) Schneider) Genotypes Growing in the Semi-arid Highlands of Sudan using ISSR Markers

The knowledge of genetic diversity of a crop like Jojoba, a commercially grown plant to produce unique liquid oil from its seed, is essential in a breeding program aiming to the development of elite genotypesfor large-scale production. This study was carried out to evaluate the genetic diversity of 25 female jojoba genotypes growing in Arkaweet Area, East Sudan, using ISSR Markers. Genomic DNA was extracted from leaves of thestudied genotypes and quantified for PCR amplification. Five ISSR primers were used for PCR amplification to investigate the genetic diversity among the female jojoba genotypes. ISSR primers showed high polymorphic pattern and produced a total of 54 polymorphic bands with an average of 10.8 polymorphic bands per primer. The average of polymorphic information content (PIC) value of 0.37 indicates moderate polymorphism. The geneticdiversity ranged from 0.01 to 0.85. The results indicate the effectiveness of using ISSR molecular markers to reveal genetic variability among the studied female jojoba genotypes, a finding that could be used for development ofelite jojoba genotypes, which provide potential for large-scale jojoba production in Sudan.