scholarly journals Clonal Reproduction and Low Genetic Diversity in Northern Australian Santalum lanceolatum (Santalaceae) Populations Highlights the Need for Genetic Rescue of This Commercially Significant Species

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 741
Author(s):  
Aaron Brunton ◽  
David J. Lee ◽  
Gabriel Conroy ◽  
Steven Ogbourne
Keyword(s):  
Genetic Diversity ◽  
Natural Populations ◽  
Life History Strategy ◽  
Conservation Strategy ◽  
Regional Differentiation ◽  
Genetic Rescue ◽  
Environmental Pressures ◽  
Northern Margin ◽  
Low Genetic Diversity ◽  
Wild Harvesting

Genetic diversity and the extent of clonality in a plant species can significantly influence its reproductive success. Whilst clonality can be an effective life-history strategy, in harsh environments it can lead to low levels of diversity and sexual reproductive failure. Santalum lanceolatum (Santalaceae) is a hemi-parasitic shrub endemic to the monsoonal dry tropics of northern Australia, which was harvested for its oil-rich heartwood from natural populations in Cape York, Australia. Despite wild harvesting ending over 70 years ago, populations in the region are currently declining. The aims of this study were to examine genetic variation, population genetic structure, inbreeding and clonality of six S. lanceolatum populations from this northern margin of the species range. Analyses of twelve microsatellite markers showed S. lanceolatum had low genetic diversity (AR = 2.776, HE = 0.409), evidence of regional differentiation (FST = 0.307–0.424) and negligible inbreeding levels (F = −0.052). Clonality investigations revealed 135 genets among 200 samples, suggesting that the clonal structure of S. lanceolatum may be limiting the potential for sexual reproduction and natural recruitment. We recommend a conservation strategy involving genetic rescue to prevent the further decline and potential local extinction from a variety of environmental pressures and human activities.

Sperm motility and offspring pre- and post-hatching survival in hybridization crosses among a landlocked and two anadromous Atlantic salmon populations: implications for conservation

2020 ◽  
Author(s):  
Aslak Tiuna Eronen ◽  
Jukka Kekäläinen ◽  
Jorma Piironen ◽  
Pekka Hyvärinen ◽  
Hannu Huuskonen ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Sperm Motility ◽  
First Generation ◽  
Hybrid Vigor ◽  
Outbreeding Depression ◽  
Genetic Rescue ◽  
Low Genetic Diversity ◽  
Salmon Eggs ◽  
Salmon Population ◽  
Lake Saimaa

The landlocked salmon (Salmo salar m. sebago) endemic to Lake Saimaa, Finland, is critically endangered and severely threatened by low genetic diversity and inbreeding. To explore the possibility of increasing the genetic diversity of threatened salmon populations by controlled hybridization (genetic rescue), we studied sperm motility and offspring pre- and post-hatching survival in hybridization crosses of landlocked salmon with two geographically close anadromous salmon populations (Rivers Neva and Tornio) relative to the pure-bred populations. While some degree of gametic incompatibility between landlocked and Tornio salmon cannot be ruled out, there were no indications of outbreeding depression in survival traits in these first-generation hybridizations. Instead, pre-hatching survival of landlocked salmon eggs fertilized with Neva salmon sperm and post-hatching survival of anadromous salmon eggs fertilized with landlocked salmon sperm were higher than in pure-bred landlocked salmon. These differences might imply genetic rescue effects (hybrid vigor), although there were also strong maternal effects involved. Our results on early viability point to the possibility of applying genetic rescue to the landlocked salmon population by hybridization with an anadromous population.

Low genetic diversity at allozyme loci in Juglans cinerea

2000 ◽  
Vol 78 (9) ◽  
pp. 1238-1243 ◽  
Author(s):  
Ricardo Morin ◽  
Jean Beaulieu ◽  
Marie Deslauriers ◽  
Gaëtan Daoust ◽  
Jean Bousquet
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Deciduous Forest ◽  
Polymorphic Locus ◽  
Natural Populations ◽  
Minor Component ◽  
Temperate Deciduous Forest ◽  
Juglans Cinerea ◽  
Low Genetic Diversity ◽  
Allozyme Loci

Butternut (Juglans cinerea L.) is a minor component of the temperate deciduous forest region of northeastern North America, but it is severely affected by the butternut canker (Sirococcus clavigignenti-juglandacearum Nair, Kostichka, and Kuntz) in the southern part of its natural range. Genetic diversity and population structure in as-yet unaffected or only slightly affected natural populations were evaluated at 12 isozyme loci. The genetic diversity estimates were low with values much below those estimated in other species of the same genus or in boreal tree species, with 25 and 13.9% polymorphic loci at the species and population levels, respectively; 1.3 and 2.3 alleles per locus and per polymorphic locus, respectively, at the species level; and an average observed heterozygosity of 0.028. Population differentiation was low, with the exception of one unique population. The implications for advanced conservation are discussed.Key words: butternut, isozymes, Sirococcus, canker, population structure.

scholarly journals DNA profiling and assessment of genetic diversity of relict species Allium altaicum Pall. on the territory of Altai

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10674
Author(s):  
Oxana Khapilina ◽  
Olesya Raiser ◽  
Alevtina Danilova ◽  
Vladislav Shevtsov ◽  
Ainur Turzhanova ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Endangered Species ◽  
Biological Diversity ◽  
Vegetative Reproduction ◽  
Natural Populations ◽  
Mobile Genetic Elements ◽  
Ice Age ◽  
Conservation Strategy ◽  
Relict Species ◽  
Genetic Elements

Analysis of the genetic diversity of natural populations of threatened and endangered species of plants is a main aspect of conservation strategy. The endangered species Allium altaicum is a relict plant of the Ice Age and natural populations are located in extreme climatic conditions of Kazakstan’s Altai Mountains. Mobile genetic elements and other interspersed repeats are basic components of a eukaryote genome, which can activate under stress conditions and indirectly promote the survival of an organism against environmental stresses. Detections of chromosomal changes related to recombination processes of mobile genetic elements are performed by various PCR methods. These methods are based on interspersed repeat sequences and are an effective tool for research of biological diversity of plants and their variability. In our research, we used conservative sequences of tRNA primer binding sites (PBS) when initializing the retrotransposon replication as PCR primers to research the genetic diversity of 12 natural populations of A. altaicum found in various ecogeographic conditions of the Kazakhstani Altai. High efficiency of the PBS amplification method used was observed already at the intrapopulation level. Unique amplicons representative of a certain population were found at the intrapopulation level. Analysis of molecular dispersion revealed that the biodiversity of populations of mountainous and lowland A. altaicum is due to intrapopulation differences for climatic zones of habitation. This is likely conditional upon predominance of vegetative reproduction over seed reproduction in some populations. In the case of vegetative reproduction, somatic recombination related to the activity of mobile genetic elements are preserved in subsequent generations. This leads to an increase of intrapopulation genetic diversity. Thus, high genetic diversity was observed in populations such as A. altaicum located in the territory of the Kalbinskii Altai, whereas the minimum diversity was observed in the populations of the Leninororsk ecogeographic group. Distinctions between these populations were also identified depending on the areas of their distribution. Low-land and mid-mountain living environments are characterized by a great variety of shapes and plasticity. This work allowed us to obtain new genetic data on the structure of A. altaicum populations on the territory of the Kazakhstan Altai for the subsequent development of preservation and reproduction strategies for this relict species.

Development of retrotransposon-based SSAP molecular marker system for study of genetic diversity in sea holly (Eryngium maritimum L.)

2010 ◽  
Vol 8 (3) ◽  
pp. 258-266 ◽  
Author(s):  
Baiba Ievina ◽  
Naeem H. Syed ◽  
Andrew J. Flavell ◽  
Gederts Ievinsh ◽  
Nils Rostoks
Keyword(s):  
Genetic Diversity ◽  
Molecular Marker ◽  
Plant Species ◽  
Natural Populations ◽  
Wild Plant ◽  
Northern Europe ◽  
Marker System ◽  
Northern Margin ◽  
Wild Plant Species ◽  
Eryngium Maritimum

Eryngium maritimum L. is a wild plant species threatened or endangered in most of Northern Europe, where species is on the northern margin of its distribution range. Recent studies have found reduction of size and even extinction of many populations. Assessment of genetic diversity in natural populations of endangered wild plant species can reflect condition and fitness of particular population and inform decisions on appropriate conservation measures. Application of inter simple sequence repeat markers and chloroplast DNA sequencing could not resolve genetic relationship between E. maritimum populations in Northern Europe. Therefore, the more sensitive retrotransposon-sequence-specific amplification polymorphism (SSAP) molecular marker system was developed. Six Ty1-copia long terminal repeat retrotransposons were isolated from E. maritimum genome (Tem1–Tem6) and assessed for their utility as molecular markers in this species. Two retrotransposons – Tem2 and Tem5 – were recognized as most informative based on the level of polymorphism and SSAP banding pattern quality. On average, 20.4% of SSAP bands were polymorphic for the five most informative primer combinations in a set of 150 Northern European E. maritimum plants from 13 locations, providing a useful tool for assessment of genetic diversity in this endangered species.

scholarly journals Characterization of Trichodesmium spp. by Genetic Techniques

2002 ◽  
Vol 68 (5) ◽  
pp. 2236-2245 ◽  
Author(s):  
K. M. Orcutt ◽  
U. Rasmussen ◽  
E. A. Webb ◽  
J. B. Waterbury ◽  
K. Gundersen ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Natural Populations ◽  
Sargasso Sea ◽  
Closely Related Species ◽  
Trichodesmium Erythraeum ◽  
Low Genetic Diversity ◽  
Gradient Gel Electrophoresis ◽  
Genetic Techniques

ABSTRACT The genetic diversity of Trichodesmium spp. from natural populations (off Bermuda in the Sargasso Sea and off North Australia in the Arafura and Coral Seas) and of culture isolates from two regions (Sargasso Sea and Indian Ocean) was investigated. Three independent techniques were used, including a DNA fingerprinting method based on a highly iterated palindrome (HIP1), denaturing gradient gel electrophoresis of a hetR fragment, and sequencing of the internal transcribed spacer (ITS) of the 16S-23S rDNA region. Low genetic diversity was observed in natural populations of Trichodesmium spp. from the two hemispheres. Culture isolates of Trichodesmium thiebautii, Trichodesmium hildebrandtii, Trichodesmium tenue, and Katagnymene spiralis displayed remarkable similarity when these techniques were used, suggesting that K. spiralis is very closely related to the genus Trichodesmium. The largest genetic variation was found between Trichodesmium erythraeum and all other species of Trichodesmium, including a species of Katagnymene. Our data obtained with all three techniques suggest that there are two major clades of Trichodesmium spp. The HIP1 fingerprinting and ITS sequence analyses allowed the closely related species to be distinguished. This is the first report of the presence of HIP1 in marine cyanobacteria.

Cyanogenic polymorphism as an indicator of genetic diversity in the rarespecies Eucalyptus yarraensis (Myrtaceae)

2002 ◽  
Vol 29 (12) ◽  
pp. 1445 ◽  
Author(s):  
Jason Q. D. Goodger ◽  
Ian E. Woodrow
Keyword(s):  
Genetic Diversity ◽  
Effective Means ◽  
Natural Populations ◽  
Population Variation ◽  
Conservation Strategy ◽  
Narrow Sense Heritability ◽  
Specialist Herbivores ◽  
Cyanogenic Plants ◽  
Physical And Chemical ◽  
First Time

The rare Australian tree Eucalyptus yarraensis Maiden & Cambage is cyanogenic, a quantitative trait potentially indicative of genetic diversity. Cyanogenic plants are capable of releasing cyanide from endogenous cyanide-containing compounds. Cyanide is toxic or deterrent to generalist or non-adapted specialist herbivores. Consequently, cyanogenic plants are afforded an effective means of chemical defense. In this paper we characterize quantitative variation in cyanogenic capability, known as cyanogenic polymorphism, in E. yarraensis for the first time. We show that the cyanogenic glucoside prunasin (R-mandelonitrile-β-D-glucoside) is the only cyanogenic compound in E. yarraensis foliage. We also show that two natural populations of E. yarraensis display extensive intra- and inter-population variation in foliar prunasin concentration. The high prunasin concentrations reported in this paper represent the highest yet recorded for mature eucalypt leaves. The cyanogenic variation could not be attributed to measured physical and chemical parameters, supporting the hypothesis that the variation is genetically based. A preliminary progeny trial also supports this hypothesis, with narrow sense heritability estimated at 1.17 from three half-sibling families. The variation in cyanogenic capability may be a useful tool in the development of a conservation strategy for the species.

Genetic structure and proposed conservation strategy for natural populations of Calycanthus chinensis Cheng et S.Y. Chang (Calycanthaceae)

2008 ◽  
Vol 88 (1) ◽  
pp. 179-186 ◽  
Author(s):  
Chu-Chuan Fan ◽  
Nicola Pecchioni ◽  
Long-Qing Chen
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
Gene Diversity ◽  
Genetic Relationships ◽  
Natural Populations ◽  
Population Level ◽  
Conservation Strategy ◽  
Information Index

Calycanthus chinensis Cheng et S.Y. Chang, a tertiary relic species in China, is a shade-loving and deciduous bush withan elegant shape and beautiful flower of high ornamental value. It was widely planted in gardens and miniature scapes in China.The objective of this study was to characterize the genetic variation and structure in the three extant populations of the species, in order to provide useful information for a future conservation strategy. Twenty-two of 120 RAPD primers were selected and a total of 257 stable and clear DNA fragments were scored. Calycanthus chinensis showed a lower level of genetic diversity. At the population level, the percentage of polymorphic loci, Nei's gene diversity and Shannon’s information index were 40.9%, 0.1641 and 0.2386, respectively; while at the species level, the corresponding values were 59.1%, 0.2097 and 0.3123, respectively. The estimates of genetic differentiation based on Shannon’s information index (0.2360), Nei’s gene diversity (0.2175) and AMOVA (24.94%) were very similar, and significantly higher than the average genetic differentiation reported in outcrossed spermatophyte. So it suggested high genetic differentiation emerged among populations of C. chinensis. Genetic relationships among populations were assessed by Nei’s standard genetic distance, which suggested that the Tiantai population was genetically distinct from the other two populations. Moreover, the genetic distance was significantly correlated with geographical distance among populations (r = 0.997, t > t0.05). The gene flow (Nm) was 0.8994, indicating that gene exchange among populations was restricted. A conservation strategy was proposed based on the low gene flow and habitat deterioration, which are contributing to the endangered status of this species. Key words: Genetic diversity, endangered plant, population genetics, RAPD

Genetic diversity of mungbean (Vigna radiata L.) germplasm in Indonesia

2014 ◽  
Vol 12 (S1) ◽  
pp. S91-S94 ◽  
Author(s):  
Puji Lestari ◽  
Sue Kyung Kim ◽  
Reflinur ◽  
Yang Jae Kang ◽  
Nurwita Dewi ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Ssr Markers ◽  
Vigna Radiata ◽  
Diversity Index ◽  
Polymorphic Information Content ◽  
Conservation Strategy ◽  
Low Genetic Diversity ◽  
Breeding Programmes ◽  
The Mean ◽  
Simple Sequence

Despite widespread mungbean [Vigna radiata (L.) Wilczek] consumption in Indonesia, few molecular studies have been carried out on accessions and available data are minimal. In this study, we used 30 newly developed simple sequence repeat (SSR) markers designed from the mapped sequence scaffolds of the Korean Sunhwanokdu and Gyeonggijaerae 5 mungbean genomes. These markers were used to examine loci in 83 mungbean accessions collected from diverse geographical areas in Indonesia. A total of 107 alleles were detected among the accessions with 29 polymorphic markers. However, the mean of polymorphic information content (0.33) value and diversity index (0.38) value was indicative of low genetic diversity in this germplasm. The mungbean population structure was not clearly differentiated and the number of subpopulations was unclear. Neighbour-joining tree analysis revealed that the genetic cluster did not reflect the geographical origin of the accessions. Interestingly, the most agriculturally improved varieties were genetically similar to some landraces from one of the main mungbean-producing regions. These newly developed SSR markers could be useful for detecting genetic variability as a basis for establishing a conservation strategy for mungbean germplasm with the aim of enhancing Indonesian breeding programmes.

Genetic diversity among natural populations of Agathis borneensis (Araucariaceae), a tropical rain forest conifer from Brunei Darussalam, Borneo, Southeast Asia

1992 ◽  
Vol 70 (10) ◽  
pp. 1945-1949 ◽  
Author(s):  
Keiko Kitamura ◽  
Mohamad Yusof Bin Abdul Rahman
Keyword(s):  
Genetic Diversity ◽  
Southeast Asia ◽  
Rain Forest ◽  
Tropical Rain Forest ◽  
Natural Populations ◽  
Conservation Strategy ◽  
Restricted Gene Flow ◽  
Isozyme Electrophoresis ◽  
Brunei Darussalam ◽  
Population Component

Agathis is a genus of tropical conifers that occurs mainly in Southeast Asia. Because of its production of good softwood, many stands of Agathis have been harvested. We provide an estimate of genetic variation within and among populations of Agathis borneensis in Brunei Darussalam, Southeast Asia. Five populations were investigated using isozyme electrophoresis. We investigated a total of 17 putative loci, five of which were polymorphic. Estimated total heterozygosity was 0.122. Heterozygosity within populations was 0.106. The population structure did not deviate significantly from Hardy–Weinberg expectations. Nei's coefficient of gene differentiation indicated that the among-population component of genetic diversity represents 14% of the total population component. The low level of genetic diversity and the large diversity among populations were the opposite of that for conifers in the temperate zone, because of the small size of each population. The large diversity among populations indicated the restricted gene flow resulting from the asynchronous flowering of this species. The genetic distance indicated that A. borneensis in Brunei could be classified in two groups, with one isolated population considerably different from the others both genetically and ecologically. The conservation strategy is discussed from the viewpoint of genetic resources. Key words: Agathis borneensis, Araucariaceae, Brunei Darussalam, genetic diversity, isozyme, tropical rain forest.

scholarly journals Genetic diversity and spatial structure of the imperiled European population of Malus trilobata in Greece

Genetika ◽  
2021 ◽  
Vol 53 (1) ◽  
pp. 103-119
Author(s):  
Konstantina Balaska ◽  
George Adamidis ◽  
Georgios Varsamis ◽  
Kyriaki Papalazarou ◽  
Paraskevi Karanikola ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Forest Fires ◽  
Agricultural Land ◽  
European Population ◽  
Flight Behavior ◽  
Conservation Strategy ◽  
Low Genetic Diversity ◽  
Genomic Marker ◽  
Genomic Markers ◽  
Nuclear Microsatellite

Malus trilobata, is a rare tree species occurring in several small and disjunct populations in the eastern part of the Mediterranean basin. The main European population is found in the region of Evros (NE Greece) and is divided in five distinct subpopulations following the species geographical pattern. The genetic diversity of approximately the entire population (69 trees) was analyzed using nuclear microsatellite and random genomic markers. Polymorphism was discovered in 29 out of 45 genomic marker loci (64.44%), while for nuclear microsatellite markers, all three loci were polymorphic with an average of 3.75 alleles per locus. Our results unraveled a specific grouping pattern for both markers. Both genetic markers exhibited relatively low genetic diversity which is in accordance with the prevalent perception that species with fragmented distributions tend to have low genetic diversity, while the differentiation among individuals, revealed a patchy pattern among small groups of trees separated by roads, firebreaks or distance. These results indicate a high genetic fragmentation level for the main European population of M. trilobata, while the presence of roads, firebreaks, conifer plantations and agricultural land, seem to function as potential barriers to gene flow. Consequently, and since it is well-documented that bees hesitate to change foraging patches, as long as their food is abundant, the observed genetic differentiation patterns could be partially attributed to the foraging and flight behavior of bees, which are the main pollinators of the species. The low levels of available genetic diversity combined with the small overall population and repeated events of forest fires inside the M. trilobata distribution, perils the survival of the species and imposes the necessity for a thoroughly organized conservation strategy.

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