scholarly journals Spatial Structure and Genetic Variation of a Mangrove Species (Avicennia marina (Forssk.) Vierh) in the Farasan Archipelago

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1287
Author(s):  
Rahmah N. Al-Qthanin ◽  
Samah A. Alharbi
Keyword(s):  
Genetic Variation ◽  
Genetic Differentiation ◽  
Species Conservation ◽  
Natural Populations ◽  
Avicennia Marina ◽  
Conservation Strategies ◽  
Isolated Populations ◽  
Mangrove Species ◽  
Population Genetic Differentiation ◽  
Sea Currents

Avicennia marina (Forssk.) Vierh is distributed in patches along the Farasan archipelago coast and is the most common mangrove species in the Red Sea. However, to date, no studies have been directed towards understanding its genetic variation in the Farasan archipelago. In this investigation, genetic variations within and among natural populations of Avicennia marina in the Farasan archipelago were studied using 15 microsatellite markers. The study found 142 alleles on 15 loci in nine populations. The observed (Ho) and expected (He) heterozygosity values were 0.351 and 0.391, respectively, which are much lower than those of earlier studies on A. marina in the Arabian Gulf. An inbreeding effect from self-pollination might explain its heterozygote deficiency. Population genetic differentiation (FST = 0.301) was similar to other mangrove species. Our findings suggest that the sea current direction and coastal geomorphology might affect genetic dispersal of A. marina. The more isolated populations with fewer connections by sea currents exhibited lower genetic variation and differentiation between populations. The genetic clustering of populations fell into three main groups—Group 1 (populations of Farasan Alkabir Island), Group 2 (populations of Sajid Island), and Group 3 (mix of one population of Farasan Alkabir Island and a population of Zifaf Island). More genetic variation and less genetic differentiation occurred when the population was not isolated and had a direct connection with sea currents. Both of these factors contributed to limited propagule dispersal and produced significant structures among the population. It is expected that the results of this research will be useful in determining policy and species-conservation strategies and in the rehabilitation of A. marina mangrove stands on the Farasan islands in an effort to save this significant natural resource.

Genetic diversity and differentiation in populations of Japanese stone pine (Pinuspumila) in Japan

1996 ◽  
Vol 26 (8) ◽  
pp. 1454-1462 ◽  
Author(s):  
Naoki Tani ◽  
Nobuhiro Tomaru ◽  
Masayuki Araki ◽  
Kihachiro Ohba
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Genetic Differentiation ◽  
Phylogenetic Trees ◽  
Genetic Relationships ◽  
Natural Populations ◽  
Group Method ◽  
Stone Pine ◽  
Arithmetic Means ◽  
Pair Group

Japanese stone pine (Pinuspumila Regel) is a dominant species characteristic of alpine zones of high mountains. Eighteen natural populations of P. pumila were studied in an effort to determine the extent and distribution of genetic diversity. The extent of genetic diversity within this species was high (HT = 0.271), and the genetic differentiation among populations was also high (GST = 0.170) compared with those of other conifers. In previous studies of P. pumila in Russia, the genetic variation within the species was also high, but the genetic differentiation among populations was low. We infer that this difference originates from differences in geographic distribution and ecological differences between the two countries. The genetic variation within each population tended, as a whole, to be smaller within marginal southern populations than within northern populations. Genetic relationships among populations reflect the geographic locations, as shown by unweighted pair-group method with arithmetic means and neighbor-joining phylogenetic trees.

scholarly journals Population structure and adaptive variation of Helichrysum italicum (Roth) G. Don along eastern Adriatic temperature and precipitation gradient

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tonka Ninčević ◽  
Marija Jug-Dujaković ◽  
Martina Grdiša ◽  
Zlatko Liber ◽  
Filip Varga ◽  
...  
Keyword(s):  
Population Structure ◽  
Genetic Variation ◽  
Genetic Differentiation ◽  
Environmental Gradient ◽  
Conservation Strategies ◽  
Mediterranean Plants ◽  
Outlier Loci ◽  
Precipitation Seasonality ◽  
Genetic Diversity And Structure ◽  
Bioclimatic Variables

AbstractImmortelle (Helichrysum italicum (Roth) G. Don; Asteraceae) is a perennial plant species native to the Mediterranean region, known for many properties with wide application mainly in perfume and cosmetic industry. A total of 18 wild H. italicum populations systematically sampled along the eastern Adriatic environmental gradient were studied using AFLP markers to determine genetic diversity and structure and to identify loci potentially responsible for adaptive divergence. Results showed higher levels of intrapopulation diversity than interpopulation diversity. Genetic differentiation among populations was significant but low, indicating extensive gene flow between populations. Bayesian analysis of population structure revealed the existence of two genetic clusters. Combining the results of FST - outlier analysis (Mcheza and BayeScan) and genome-environment association analysis (Samβada, LFMM) four AFLP loci strongly associated with the bioclimatic variables Bio03 Isothermality, Bio08 Mean temperature of the wettest quarter, Bio15 Precipitation seasonality, and Bio17 Precipitation of driest quarter were found to be the main variables driving potential adaptive genetic variation in H. italicum along the eastern Adriatic environmental gradient. Redundancy analysis revealed that the partitioning of genetic variation was mainly associated with the adaptation to temperature oscillations. The results of the research may contribute to a clearer understanding of the importance of local adaptations for the genetic differentiation of Mediterranean plants and allow the planning of appropriate conservation strategies. However, considering that the identified outlier loci may be linked to genes under selection rather than being the target of natural selection, future studies must aim at their additional analysis.

Genetic Differentiation in Natural Populations of Grevillea robusta

1997 ◽  
Vol 45 (4) ◽  
pp. 669 ◽  
Author(s):  
C. E. Harwood ◽  
G. F. Moran ◽  
J. C. Bell
Keyword(s):  
Genetic Variation ◽  
Genetic Differentiation ◽  
Natural Populations ◽  
Grevillea Robusta ◽  
Distance Analysis ◽  
Riverine Habitat ◽  
Natural Range ◽  
Isozyme Loci ◽  
The Difference ◽  
Genetic Distance Analysis

Genetic variation in 23 natural populations of Grevillea robusta A.Cunn. from across the natural range of the species was examined using 20 isozyme loci assayed in young seedlings. Mean expected heterozygosity per population, He , varied from 0.080 to 0.131 with an average of 0.105. The genetic diversity of individual populations did not appear to be related to their ecological characteristics (araucarian vine forest or riverine habitat types) or their geographic locations. A genetic distance analysis indicated a significant separation of the populations into two regional groups, eight from the northern part of the natural range and the remaining 15 from central and southern areas. Between-population differences accounted for 17.9% of the total genetic variation, one-third of which was attributable to the difference between the two regional groups. Most alleles at the 20 loci occurred across most or all of the geographic range. This, and the low level of genetic differentiation between populations, suggest that genetic exchange between populations has been maintained, despite the pattern of natural distribution of the species in small, separated populations.

scholarly journals GENETIC VARIATION IN NATURAL POPULATIONS OF FIVE DROSOPHILA SPECIES AND THE HYPOTHESIS OF THE SELECTIVE NEUTRALITY OF PROTEIN POLYMORPHISMS

Genetics ◽  
1974 ◽  
Vol 77 (2) ◽  
pp. 343-384
Author(s):  
Francisco J Ayala ◽  
Martin L Tracey ◽  
Lorraine G Barr ◽  
John F McDonald ◽  
Santiago Pérez-Salas
Keyword(s):  
Genetic Variation ◽  
Genetic Differentiation ◽  
Natural Populations ◽  
Evolutionary Divergence ◽  
Average Value ◽  
Local Populations ◽  
Selective Neutrality ◽  
Average Proportion ◽  
Substantial Degree ◽  
Protein Polymorphisms

ABSTRACT We have studied genetic variation at 30-32 loci coding for enzymes in natural populations of five species of Drosophila. The average proportion of heterozygous loci per individual is 17.7 ± 0.4%. The average proportion of polymorphic loci per population is 69.2 ± 2.6% or 49.8 ± 2.2%, depending on what criterion of polymorphism is used. The following generalizations are advanced: (1) The amount of genetic polymorphism varies considerably from locus to locus. (2) At a given locus, populations of the same species are very similar in the amount and pattern of genetic variation. (3) However, at some loci large differences sometimes occur between local populations of the same species. (4) The amount of variation at a given locus is approximately the same in all five species. (5) When different species are compared, the pattern of the variation is either essentially identical or totally different at a majority of loci. We have tested the hypothesis that protein polymorphisms are selectively neutral by examining four predictions derived from the hypothesis. Our results are at variance with every one of the predictions. We have measured the amount of genetic differentiation, D, between taxa of various degrees of evolutionary divergence. The average value of D is 0.033 for local populations, 0.228 for subspecies, 0.226 for semispecies, 0.538 for sibling species, and 1.214 for morphologically distinguishable species. Our results indicate that a substantial degree of genetic differentiation (22.8 allelic substitutions for every 100 loci) occurs between allopatric populations that have diverged to the point where they might become different species if they were to become sympatric. However, very little additional genetic change is required for the development of complete reproductive isolation. After the speciation process is completed, species continue to diverge genetically from each other.

scholarly journals RAPD analysis of the genetic diversity of two natural populations of Paphiopedilum villosum var. Annamense rolfe. in the Lam Vien plateau

2016 ◽  
Vol 14 (3) ◽  
pp. 451-459
Author(s):  
Đặng Thị Thắm ◽  
Nông Văn Duy ◽  
Trần Văn Tiến ◽  
Lê Ngọc Triệu ◽  
Khuất Hữu Trung ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Wild Population ◽  
Gene Diversity ◽  
Species Conservation ◽  
Natural Populations ◽  
Small Population ◽  
Habitat Destruction ◽  
Similarity Coefficients ◽  
Population Sizes ◽  
Two Populations

Paphiopedilum villosum var. annamense Rolfe. is the attractive pot plant characterize by its larger and beautiful flower. Wild population of that orchid are now considered to be rare in nature as a result of habitat destruction and commercial preference. Thus, it is very important that actions should be taken to conserve this orchid before it becomes extinct. The information of genetic variation at both population and species levels is a scientific basic for species conservation. In this research, two populations of Paphiopedilum villosum var. annamense Rolfe were collected in Lam Dong province, Vietnam for analysing of genetic variation. RAPD directive was used to examine genetic variability in 20 individuals of two populations. The results showed that 25 bands were recorded from 12 specific identification primers. The percentages of polymorphic loci at species and population levels in the research were not high (Pt = 74.07%; P1 = 67.90%; P2 = 62.35%). However, in the first population, a higher percentage of polimorphic loci was observed as in the second one. Significant heterozygosity at both population and species levels was also low (HE1 = 0.23; HE2 = 0.18; and HEt = 0.25). The total gene diversity at the species level was partitioned primarily between two populations, as show by low GST= 0.17. Genetic distance between two populations was low (D12 = 0.079). In the orther hand, Genetic similarity coefficients between individuals in the general population were ranged from 0.57 to 0.91. The results suggested that the small population sizes in isolation had led to increase of inbred individuals within populations. Some solutions to the conservation and sustainable development have been mentioned.

Lack of allozymic variation in disjunct Newfoundland populations of red pine (Pinusresinosa)

1991 ◽  
Vol 21 (4) ◽  
pp. 525-528 ◽  
Author(s):  
A. Mosseler ◽  
D. J. Innes ◽  
B. A. Roberts
Keyword(s):  
Genetic Variation ◽  
Genetic Differentiation ◽  
Cellulose Acetate ◽  
Gel Electrophoresis ◽  
Red Pine ◽  
Enzyme Electrophoresis ◽  
Isolated Populations ◽  
Putative Gene ◽  
Enzyme Gene ◽  
Enzyme Systems

Disjunct, geographically isolated populations of red pine (Pinusresinosa Ait.) on the island of Newfoundland were investigated by enzyme electrophoresis to determine if these populations were genetically distinct from a range-wide sample of mainland populations. Genetic variation at 23 putative gene loci from 12 enzyme systems was assayed by cellulose acetate gel electrophoresis. Each of the 96 trees sampled was monomorphic for all enzyme gene loci assayed, and no genetic differentiation between Newfoundland and mainland populations was detected. The striking lack of genetic variation at enzyme gene loci in red pine has been confirmed for the most isolated populations at the extreme northeastern margins of its range.

scholarly journals Genetic Diversity of the Relict Plant Taiwania cryptomerioides Hayata (Cupressaceae) in Mainland China

2008 ◽  
Vol 57 (1-6) ◽  
pp. 242-249 ◽  
Author(s):  
Zhong-Chao Li ◽  
Xiao-Lan Wang ◽  
Xue-Jun Ge
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Genetic Differentiation ◽  
Gene Diversity ◽  
Mainland China ◽  
Small Population ◽  
Conservation Strategies ◽  
Biogeographic History ◽  
Inter Simple Sequence Repeats ◽  
Taiwania Cryptomerioides

Abstract The genetic diversity and differentiation of five populations of Taiwania cryptomerioides Hayata in mainland China were investigated using inter-simple sequence repeats (ISSR). In comparison with other coniferous species, T. cryptomerioides from mainland China possesses little genetic variation, particularly at the level of individual populations (the percentage of polymorphic loci, Nei’s gene diversity and Shannon’s indices of diversity at the species and population levels are 38.02%, 0.1326, 0.1986 and 9.27%, 0.035, 0.0518 respectively). In contrast, the level of population differentiation is much higher (GST: 0.7269; Shannon’s genetic differentiation: 0.7392; Hickory è B: 0.668; AMOVA genetic differentiation: 72.37%). The genetic divergence of pairs of populations was not significantly correlated with the geographical distance separating them. Current patterns of genetic variation were related to biogeographic history and the small population size. On the basis of these findings, we discuss the development of conservation strategies for this endangered species.

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