Analysis of Genetic Variation in Natural Populations of Medicago truncatula of Southern Tunisian Ecological Areas, Using Morphological Traits and SSR Markers

2009 ◽  
Vol 2 (3-4) ◽  
pp. 122-132 ◽  
Author(s):  
Soumaya Arraouadi ◽  
Mounawer Badri ◽  
Cheruth Abdul Jaleel ◽  
Naceur Djébali ◽  
Houcine Ilahi ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Ssr Markers ◽  
Medicago Truncatula ◽  
Morphological Traits ◽  
Natural Populations

scholarly journals 561 Using AFLPs to Examine Genetic Diversity in Umbrella Fern

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 543A-543
Author(s):  
F.J. Keiper ◽  
R. McConchie
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Molecular Markers ◽  
Dna Markers ◽  
Morphological Traits ◽  
Natural Populations ◽  
Cost Effective ◽  
Molecular Techniques ◽  
Breeding Systems ◽  
Detailed Knowledge

Umbrella fern [Sticherus flabellatus (R. Br.) St John] is a successful Australian native foliage product. Currently, all umbrella fern sold on the market is bush-harvested. To meet the growing demand for this product on local and international markets, a commercially viable method for its production must be developed, with effective management of the germplasm resource in terms of conservation and exploitation. To manage this resource, breeders require a detailed knowledge of the amount and distribution of genetic variability within the species. Traditionally, plant breeders focus on a combination of agronomic and morphological traits (phenotype) to measure genetic diversity. In umbrella fern there are a limited number of morphological traits, and these are influenced by environmental factors and therefore do not reflect true genetic diversity. To overcome these problems, molecular techniques such as PCR-based DNA markers are used to complement traditional strategies for genotype assessment. DNA markers have the advantages of being independent of environmental effects, as well as being fast, cost-effective, reproducible, and largely accessible to the nonmolecular geneticist. Amplified fragment length polymorphisms (AFLPs) fulfil many of the desirable features of molecular markers, as well as requiring little knowledge of the genome to be investigated. AFLPs have been used widely in the analysis of breeding systems, ecogeographical variation, and genetic variation within and between natural populations. To date there are no published accounts of DNA molecular marker research on umbrella fern. A DNA extraction protocol has been developed for this species, and AFLP markers have been used to analyse genetic diversity within and between natural populations sampled in the Sydney Basin. A large number of polymorphic loci were revealed using 11 primer combinations. The genetic variation detected was partitioned between rather than within populations, suggesting that the mating system in Sticherus is primarily inbreeding. Data will be presented illustrating AFLPs as useful molecular markers for assessing genetic diversity within and between populations of umbrella fern and providing insight on the breeding system used by the species.

scholarly journals Variation in Morphological Traits and Yield Evaluation among Natural Populations of Medicago truncatula and Medicago laciniata

2019 ◽  
Vol 12 (3) ◽  
pp. 596-603
Author(s):  
Abderrezak Chebouti ◽  
Nassila Meziani ◽  
Fadila Bessedik ◽  
Mohamed Laib ◽  
Soraya Amrani
Keyword(s):  
Medicago Truncatula ◽  
Morphological Traits ◽  
Natural Populations

scholarly journals Genetic Variation in Two Rare Endemic Mexican Trees, Magnolia sharpii and Magnolia schiedeana

2008 ◽  
Vol 57 (1-6) ◽  
pp. 348-356 ◽  
Author(s):  
A. C. Newton ◽  
J. Gow ◽  
A. Robertson ◽  
G. Williams-Linera ◽  
N. Ramírez-Marcial ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Ssr Markers ◽  
Tree Species ◽  
Cloud Forest ◽  
Natural Populations ◽  
Rflp Analysis ◽  
Conservation Strategies ◽  
Endemic Plant ◽  
Geographic Ranges ◽  
Pcr Rflp

Abstract Patterns of genetic variation were examined within two endemic tree species restricted to Mexican cloud forest, Magnolia sharpii and Magnolia schiedeana. Leaf samples collected from natural populations were analysed using PCR RFLP of cpDNA, Inter-SSR and isozyme genetic markers, which were used to test a series of hypotheses regarding patterns of intraspecific variation within the two species. Genetic diversity estimates derived from Inter-SSR markers (mean Spop of 0.56 and 0.50 for M. sharpii and M. schiedeana respectively) are comparable to values obtained for other tree species. As predicted on the basis of its larger geographic range, the degree of population differentiation was found to be higher within M. schiedeana than M. sharpii, with 12.9% and 3.4% of total variation recorded between populations for the two species respectively using isozymes, and 26% and 11% using Inter- SSR markers. Isozyme analyses indicated negative Fis values, which may be suggestive of inbreeding in populations of M. sharpii, but provided less evidence of inbreeding in M. schiedeana. On the basis of PCR RFLP analysis of cpDNA, two chloroplast types were differentiated, type A being recorded for all of the individuals of both species, with the exception of one population of M. schiedeana that was fixed for type B. These results are consistent with recent evidence suggesting that some endemic plant taxa are able to maintain relatively high diversity within populations despite the occurrence of inbreeding and genetic drift, and that species with wider geographic ranges tend to exhibit relatively high genetic differentiation among populations. Conservation strategies for these species need to take into account the significant genetic differences recorded among the populations studied.

scholarly journals POPULATION GENETICS OF ALLOZYME VARIATION IN NEUROSPORA INTERMEDIA

Genetics ◽  
1975 ◽  
Vol 80 (4) ◽  
pp. 785-805
Author(s):  
P T Spieth
Keyword(s):  
Genetic Variation ◽  
Vegetative Reproduction ◽  
Vascular Plant ◽  
Natural Populations ◽  
Allozyme Variation ◽  
Regular Feature ◽  
Local Populations ◽  
Neurospora Intermedia ◽  
Pattern Of Variation ◽  
High Level

ABSTRACT Electrophoretically detectable variation in the fungus Neurospora intermedia has been surveyed among isolates from natural populations in Malaya, Papua, Australia and Florida. The principal result is a pattern of genetic variation within and between populations that is qualitatively no different than the well documented patterns for Drosophila and humans. In particular, there is a high level of genetic variation, the majority of which occurs at the level of local populations. Evidence is presented which argues that N. intermedia has a population structure analogous to that of an annual vascular plant with a high level of vegetative reproduction. Sexual reproduction appears to be a regular feature in the biology of the species. Substantial heterokaryon function seems unlikely in natural populations of N. intermedia. Theoretical considerations concerning the mechanisms underlying the observed pattern of variation most likely should be consistent with haploid selection theory. The implications of this constraint upon the theory are discussed in detail, leading to the presentation of a model based upon the concept of environmental heterogeneity. The essence of the model, which is equally applicable to haploid and diploid situations, is a shifting distribution of multiple adaptive niches among local populations such that a given population has a small net selective pressure in favor of one allele or another, depending upon its particular distribution of niches. Gene flow among neighboring populations with differing net selective pressures is postulated as the principal factor underlying intrapopulational allozyme variation.

scholarly journals Female Genotypes Affect Sperm Displacement in Drosophila

Genetics ◽  
1998 ◽  
Vol 149 (3) ◽  
pp. 1487-1493 ◽  
Author(s):  
Andrew G Clark ◽  
David J Begun
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Natural Populations ◽  
Isogenic Line ◽  
Female Fitness ◽  
Sperm Displacement ◽  
Extensive Variation ◽  
Polymorphic Genes ◽  
Displacement Parameter ◽  
Competitive Success

Abstract Differential success of sperm is likely to be an important component of fitness. Extensive variation among male genotypes in competitive success of sperm in multiply mated females has been documented for Drosophila melanogaster. However, virtually all previous studies considered the female to be a passive vessel. Nevertheless, under certain conditions female fitness could be determined by her role in mediating use of sperm from multiple males. Here we ask whether females differ among genotypes in their tendency to exhibit last-male precedence. Competition of sperm from two tester male genotypes (bwD and B3-09, a third-chromosome isogenic line from Beltsville, MD) was quantified by doubly mating female lines that had been rendered homozygous for X, second, or third chromosomes isolated from natural populations. The composite sperm displacement parameter, P2′, was highly heterogeneous among lines, whether or not viability effects were compensated, implying the presence of polymorphic genes affecting access of sperm to eggs. Genetic variation of this type is completely neutral in the absence of pleiotropy or interaction between variation in the two sexes.

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