Genetic variation within and between populations of two endangered endemic species of the laurel forest from the Canary Islands, Myrica rivas-martinezii (Myricaceae) and Sideritis discolor (Lamiaceae)

2004 ◽  
Vol 52 (4) ◽  
pp. 471 ◽  
Author(s):  
F. Batista ◽  
N. Bouza ◽  
M. A. González-Pérez ◽  
J. Caujapé-Castells ◽  
P. A. Sosa

Myrica rivas-martinezii A.Santos and Sideritis discolor Bolle, two endangered endemic species of the laurel forest from the Canary Islands, were studied by using RAPD markers with the goal of assessing their within- and among-population apportionment of genetic variability. Ten- and 11-oligonucleotide primers assayed in three populations of each of M. rivas-martinezii and S. discolor resulted in 32 molecular markers in the former species and 49 in the latter (90.6% and 100% polymorphic, respectively). The value of the coefficient of genetic differentiation among populations was very high for M. rivas-martinezii (FST = 0.487) but only moderate for S.�discolor (FST = 0.149). These results suggest that gene flow among populations is extremely low in M.�rivas-martinezii and quite substantial in S. discolor. The UPGMA cluster obtained from Dice's coefficient mixed individuals from different populations in S. discolor but not in M. rivas-martinezii, where they were grouped by their island of occurrence. On the basis of these results and the vulnerability of these two species, we suggest protection of all natural populations. However, if habitat conservation is not possible, our results suggest that for S.�discolor, the La Virgen population would make a good donor population because of geographical and genetic factors. The high genetic differentiation detected among populations of M. rivas-martinezii suggests that each island should be considered as a distinct management unit. However, considering the situation of this species on La Palma Island with only two isolated individuals, reintroductions of germoplasma from El Hierro may be a viable way to guarantee the existence of M. rivas-martinezii in that island.

Genetics ◽  
1978 ◽  
Vol 88 (2) ◽  
pp. 367-390
Author(s):  
Ranajit Chakraborty ◽  
Paul A Fuerst ◽  
Masatoshi Nei

ABSTRACT With the aim of testing the validity of the mutation-drift hypothesis, we examined the pattern of genetic differentiation between populations by using data from Drosophila, fishes, reptiles, and mammals. The observed relationship between genetic identity and correlation of heterozygosities of different populations or species was generally in good agreement with the theoretical expectations from the mutation-drift theory, when the variation in mutation rate among loci was taken into account. In some species of Drosophila, however, the correlation was unduly high. The relationship between the mean and variance of genetic distance was also in good agreement with the theoretical prediction in almost all organisms. We noted that both the distribution of heterozygosity within species and the pattern of genetic differentiation between species can be explained by the same set of genetic parameters in each group of organisms. Alternative hypotheses for explaining these observations are discussed.


Zootaxa ◽  
2021 ◽  
Vol 5071 (3) ◽  
pp. 326-348
Author(s):  
MARC MASSA ◽  
CARLES RIBERA

The aim of this paper is to describe a new species of the genus Loxosceles Heineken & Lowe, 1832 from Morocco, Loxosceles imazighen sp. n., and to describe for the first time a female of Loxoxceles mrazig Ribera & Planas, 2009 from Tunisia. Both species live in xeric and desert environments and are located in southern Atlas Range. Molecular phylogenetic analyses, using mitochondrial (cox1, 16S) and nuclear (H3, 28S) markers, revel that these species are closely related and that they constitute a separate evolutionary lineage of L. rufescens (Dufour, 1820) and of the set of endemic species of the Canary Islands. L. imazighen sp. n. differs from L. mrazig, the closest species morphologically and geographically, in the shapes and proportions of the male palpal tibia and the shapes and dispositions of the female seminal receptacles. In addition, L. mrazig females show morphological variability in their genitalia, mainly in the inner and outer lobes. Although that variability cannot be associated with different populations, since it also appears within individual populations, and is not related to genetic or geographic distances.  


2007 ◽  
Vol 64 (1) ◽  
pp. 109-119 ◽  
Author(s):  
Alfredo Manuel Bermúdez ◽  
José María Fernández-Palacios ◽  
Juana María González-Mancebo ◽  
Jairo Patiño ◽  
José Ramón Arévalo ◽  
...  

Encuentro ◽  
2016 ◽  
pp. 28-39
Author(s):  
Arlen Tijerino ◽  
Lourdes Callejas ◽  
David A. Cerda-Granados

The goal of this study was to assess the genetic diversity of Nicaraguan populations of Cedrela odorata using Random Amplified Polymorphic DNA (RAPD) markers. Thus, genomic DNA was isolated from leaf samples collected from ninety-two trees belonging to five Nicaraguan natural populations of C. odorata. The mean number of alleles per locus, effective number of alleles per locus, percentage of polymorphic loci, genetic diversity (He ) of Nei and diversity index (Ho ) of Shannon were estimated for each population assuming that the populations were in HardyWeinberg equilibrium. Total genetic diversity was partitioned in intrapopulational and interpopulational diversity using Nei’s genetic differentiation (GST) and through an Analysis of Molecular Variance (AMOVA). The ΦST matrix was used to construct a dendrogram by the neighbor-joining method. According to values of both He and Ho , Esquipulas (Deparment of Matagalpa) presented the lowest diversity level; while La Trinidad (Department of Estelí) showed the highest diversity level. Genetic differentiation was calculated obtaining a GST value of 13.36%. AMOVA also showed a similar differentiation value ΦST =13.81%). Neighbour-joining dendrogram clustered the five populations in two groups, where the group formed by La Trinidad and El Refugio (Department of Granada) presented the biggest differentiation. Correlation between genetic and geographical distances was not found.


2020 ◽  
Author(s):  
Isabelle De Cauwer ◽  
Philippe Vernet ◽  
Sylvain Billiard ◽  
Cécile Godé ◽  
Angélique Bourceaux ◽  
...  

AbstractThe breakdown of self-incompatibility (SI) in angiosperms is one of the most commonly observed evolutionary transitions. While multiple examples of SI breakdown have been documented in natural populations, there is strikingly little evidence of stable within-population polymorphism with both inbreeding (self-compatible) and outcrossing (self-incompatible) individuals. This absence of mating system polymorphism corroborates theoretical expectations that predict that in/outbreeding polymorphism is possible only under very restricted conditions. However, theory also predicts that a diallelic sporophytic SI system facilitates the maintenance of such polymorphism. We tested this prediction by studying the mating system of Ligustrum vulgare L., an entomophilous hermaphroditic species of the Oleaceae family. Using stigma tests with controlled pollination and paternity assignment of open-pollinated progenies, we confirmed the existence of two self-incompatibility groups in this species. We also demonstrated the existence of self-compatible individuals in different populations of Western Europe arising from a mutation affecting the expression of the pollen component of SI. We then estimated the selfing rate in a garden experiment. Our results finally show that the observed low frequency of self-compatible individuals in natural populations is compatible with theoretical predictions only if inbreeding depression is very high.


Genetics ◽  
1982 ◽  
Vol 101 (2) ◽  
pp. 235-256
Author(s):  
Rama S Singh ◽  
Donal A Hickey ◽  
Jean David

ABSTRACT We have studied allozyme variation at 26 gene loci in nine populations of Drosophila melanogaster originating on five different continents. The distant populations show significant genetic differentiation. However, only half of the loci studied have contributed to this differentiation; the other half show identical patterns in all populations. The genetic differentiation in North American, European and African populations is correlated with the major climatic differences between north and south. These differences arise mainly from seven loci that show gene-frequency patterns suggestive of latitudinal clines in allele frequencies. The clinal variation is such that subtropical populations are more heterozygous than temperate populations. These results are discussed in relation to the selectionist and neutralist hypotheses of genetic variation in natural populations.


2009 ◽  
Vol 69 (2) ◽  
pp. 375-380 ◽  
Author(s):  
MF. Manica-Cattani ◽  
J. Zacaria ◽  
G. Pauletti ◽  
L. Atti-Serafini ◽  
S. Echeverrigaray

Twenty-seven accessions of Lippia alba Mill. collected in Rio Grande do Sul state, Brazil, were analysed by ISSR and RAPD markers to evaluate their genetic variability and relationships. Six ISSR primers and four RAPD primers generated 120 amplified fragments, most of which were polymorphics. The overall genetic variability among accessions was very high when compared with other plant species. The hierarchical analysis of molecular data (UPGMA) showed low relationship between accessions, and no grouping between accessions of the same chemotype. Canonical functions allowed identifying some variables related with the chemical characteristics of the essential oils. Both ISSR and RAPD markers were efficient to address the genetic diversity of L. alba, and may contribute to the conservation and breeding of this increasingly important aromatic and medicinal species.


2000 ◽  
Vol 1 (9) ◽  
pp. n/a-n/a ◽  
Author(s):  
Lisa Tauxe ◽  
Hubert Staudigel ◽  
Jan R. Wijbrans
Keyword(s):  

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