The mating system and genic diversity in Martínez spruce, an extremely rare endemic of México's Sierra Madre Oriental: an example of facultative selfing and survival in interglacial refugia

2000 ◽  
Vol 30 (7) ◽  
pp. 1156-1164 ◽  
Author(s):  
F Thomas Ledig ◽  
Basilio Bermejo-Velázquez ◽  
Paul D Hodgskiss ◽  
David R Johnson ◽  
Celestino Flores-López ◽  
...  
Keyword(s):  
Mating System ◽  
High Frequency ◽  
Expected Heterozygosity ◽  
Sierra Madre ◽  
Fixation Indices ◽  
Rare Endemic ◽  
Genic Diversity ◽  
Total Genic Diversity ◽  
Two Populations ◽  
Nei's Genetic Distance

Martínez spruce (Picea martínezii T.F. Patterson) is a conifer currently passing through a bottleneck, reduced to a few relict populations totaling less than 800 trees. We used isozyme markers to analyze the mating system and survey the level of genic diversity in two populations. The mating system was characterized by a high frequency of selfing. The multilocus outcrossing rates (tm) and 95% confidence intervals were only 0.399 (0.197 < tm < 0.601) for the smallest population and 0.589 (0.475 < tm < 0.703) or 0.685 (0.465 < tm < 0.905), depending on year, for the largest. These are among the lowest rates of outcrossing observed in conifers. The fixation indices for the two populations were -0.058 and 0.121, less than expected for such high levels of selfing. Expected heterozygosity, unbiased He, based on 22 loci in 13 enzyme systems, was 0.121 and 0.101 in the two populations. The proportion of the total genic diversity between populations, FST, was 2.4%. Nm, the number of migrants per generation, was about 1.00 or 10.17, depending on the method of estimation. The time since the two populations were isolated was estimated from Nei's genetic distance as only 150 to 15 000 years, which is consistent with a hypothesis of population collapse during late Pleistocene or Holocene warming. We discuss the implications for conservation.

scholarly journals High frequency of polyandry in a lek mating system

2002 ◽  
Vol 13 (2) ◽  
pp. 209-215 ◽  
Author(s):  
D. B. Lank
Keyword(s):  
Mating System ◽  
High Frequency ◽  
Lek Mating

Estimation of mating system parameters in two Italian natural populations of Fagussylvatica

1996 ◽  
Vol 26 (7) ◽  
pp. 1187-1192 ◽  
Author(s):  
Patrizia Rossi ◽  
Giovanni Giuseppe Vendramin ◽  
Raffaello Giannini
Keyword(s):  
Mating System ◽  
Natural Populations ◽  
Female Parent ◽  
European Beech ◽  
Allele Frequencies ◽  
Mixed Mating ◽  
System Parameters ◽  
Fixation Indices ◽  
Mixed Mating Model ◽  
Allozyme Loci

Mating system parameters were estimated in two Italian natural populations of European beech (Fagussylvatica L.) using a mixed mating model and considering seven allozyme loci (Idh-A, Lap-A, Mdh-B, Pgd-A, Pgd-B, Pgd-C, Skd-A). High values of multilocus estimates of the outcrossing rate were found in both populations, ranging from 94 to 98%. Comparison of single- and multi-locus estimates of outcrossing rates seems to indicate the presence of consanguineous matings, probably because the populations are substructured. This hypothesis seems to be confirmed by the presence of a heterogeneity of the pollen allele frequencies across female parent trees and by the significant coefficient of the regression of pollen allele frequencies on ovule genotype. Variation in the fixation indices in different life-cycle phases was observed, indicating possible presence of selective processes between seed set and sexual maturity. Possible explanations of these results are presented.

scholarly journals Impact of broadband seismology on the understanding of strong motions

1993 ◽  
Vol 83 (3) ◽  
pp. 830-850
Author(s):  
Don Helmberger ◽  
Douglas Dreger ◽  
Richard Stead ◽  
Hiroo Kanamori
Keyword(s):  
High Frequency ◽  
Strong Motion ◽  
Geometrical Spreading ◽  
Low Velocity ◽  
Sierra Madre ◽  
Broadband Seismology ◽  
Whole Space ◽  
Low Velocity Layer ◽  
Lower Crustal ◽  
Velocity Layer

Abstract Most analyses of strong motion attenuation assume simple whole-space type geometrical spreading, namely (1/R) or its modified form e−kR/R. However, broadband data presently becoming available suggests a more complex behavior with substantial crustal effects. Events such as the Sierra Madre event, M = 5.8, triggered the strong motion channels at all of the TERRAscope stations allowing for 0.01-sec sampling of the wavefield. We find that most of the well-defined crustal bodywave arrivals defined and modeled in the 1 to 0.1-hz bandpass also contain high-frequency energy. By comparing the triggered channels with the continuous channels we see that several of the more distant stations triggered on the depth phase sPmP. These phases as well as the depth phase sSmS are obvious in velocity and quite apparent in accelerations. Our best models for Southern California contain a relatively thick low-velocity layer at the surface, roughly 5 km thick with shear velocities below 3 km/sec. This layer or zone, because it appears to vary considerably, controls the wavefield at nearly all frequencies out to about 60 km and yields attenuation decay faster than (1/R). At large ranges the lower crustal triplications dominate and the attenuation curve flattens. Adding random scatters to these layered models adds additional complexity but does not alter the basic flat-layer predictions.

scholarly journals Testing the breeding strategy of Hungarian Bronze turkey strains for maintaining genetic diversity with microsatellites

2011 ◽  
Vol 54 (4) ◽  
pp. 419-429
Author(s):  
S. Kusza ◽  
S. Mihók ◽  
L. Czeglédi ◽  
A. Jávor ◽  
M. Árnyasi
Keyword(s):  
Genetic Diversity ◽  
Genetic Variability ◽  
Mating System ◽  
Breeding Strategy ◽  
Shannon Index ◽  
Inbreeding Coefficient ◽  
Control Population ◽  
Conservation Strategies ◽  
The Mean ◽  
Two Populations

Abstract. The aim of the study was to provide information on the genetic variability of the Hungarian Bronze turkey gene reserve population and its difference from the Broad-breasted turkey, and offer guidance and proposals for its future conservation strategies. Altogether, 239 Hungarian Bronze turkeys from 10 strains and 13 Broad-breasted turkeys as a control population were genotyped for 15 microsatellites. All loci were polymorphic with the average number of alleles per locus 3.20±1.146 in the Hungarian Bronze turkey. The mean expected (Hexp) and observed heterozygosity (Hobs) were not different (0.392 and 0.376, respectively) in the overall population, and similar values were obtained for hens and bucks and among hen strains. Inbreeding coefficient (FIS) and Shannon index (I) indicated that there was low inbreeding within hens and bucks. Our results confirm that the genetic diversity in the Hungarian Bronze turkey population has been preserved by the rotational mating system. Differences between the Hungarian Bronze turkey and the Broad-breasted turkey populations were determined. Nei’s unbiased values clearly indicated that the two populations are highly genetically differentiated.

scholarly journals Characterization of Nuclear Microsatellite Markers for the Narrow Endemic Syringa josikaea Jacq. fil. ex Rchb.

2013 ◽  
Vol 41 (1) ◽  
pp. 301 ◽  
Author(s):  
Bertalan LENDVAY ◽  
Andrzej PEDRYC ◽  
Mária Höhn
Keyword(s):  
Microsatellite Markers ◽  
Ornamental Plants ◽  
Enriched Library ◽  
Microsatellite Primers ◽  
Genetic Lineages ◽  
Nuclear Microsatellite ◽  
Rare Endemic ◽  
Two Populations ◽  
Pcr Conditions

The species of the genus Syringa L. are among the most popular ornamental plants worldwide. One particular species, Syringa josikaea, a rare endemic of the Carpathian Mountains, is of great conservation interest. Although microsatellite markers may be useful for studying the genetic variability of varieties and populations, no microsatellites have previously been characterized for any species of the Syringa genus. Our aim was therefore to test the applicability of microsatellite primers developed for neighboring genera (Olea and Ligustrum) and to complement these with markers isolated and characterized for S. josikaea. Twelve primer pairs of Olea and Ligustrum were tested by optimizing PCR conditions and checking the variability in 40 samples of two populations of S. josikaea. Two of them proved to be easy to PCR amplify and variable at the same time. To develop new primers we constructed a microsatellite enriched library and sequenced 48 clones. 18 sequences contained microsatellite motifs, and three of the designed primer pairs presented high allele variability. The five primer pairs characterized for S. josikaea proved to be highly informative and sufficient to distinguish between individuals. These microsatellite primers are valuable tools to study genetic variation of native populations, genetic lineages of hybrids and cultivars of S. josikaea.

Genetic differentiation, diversity, and inbreeding in the mountain monkeyflower (Mimulus caespitosus) of the Washington Cascades

1989 ◽  
Vol 67 (7) ◽  
pp. 2017-2024 ◽  
Author(s):  
Kermit Ritland
Keyword(s):  
Genetic Relationships ◽  
Genetic Distances ◽  
Washington State ◽  
Mountain Streams ◽  
Cascade Mountains ◽  
Postglacial Colonization ◽  
Expected Heterozygosity ◽  
Allozyme Loci ◽  
Nei's Genetic Distance ◽  
Washington Cascades

Mimulus caespitosus is a stoloniferous yellow monkeyflower that grows in small, perennial mountain streams. Plants from 22 populations around the crest of the Cascade Mountains in Washington State were electrophoretically assayed for 15 allozyme loci. Expected heterozygosity within populations (H), a measure of genetic diversity, averaged 0.17 and was negatively correlated with northeastward aspect. No association of H with elevation or position upstream was detected. Wright's gene fixation F averaged 0.19, indicating 20–30% selfing, and was significantly heterogeneous among populations. Nei's genetic distance D averaged 0.072, significantly above average for conspecific populations, especially considering all populations were within 11 km. Populations from the same stream have lowest D, whereas populations from the same mountainside, mountain, and region show increasing values of D. Thus, gene flow is predominant along streams and a hierarchy of genetic relationships exists. It was expected that because this area was heavily glaciated during the Pleistocene, postglacial colonization by refugial populations would result in strong clusters of populations from adjacent streams sharing the same refugia. However, a dendrogram of genetic distances showed few statistically significant clusters of populations from different streams.

Genetic diversity and mating system of post-fire and post-harvest black spruce: an investigation using codominant sequence-tagged-site (STS) markers

2001 ◽  
Vol 31 (1) ◽  
pp. 32-40 ◽  
Author(s):  
Daniel J Perry ◽  
Jean Bousquet
Keyword(s):  
Genetic Diversity ◽  
Mating System ◽  
Negative Impact ◽  
Black Spruce ◽  
Sequence Tagged Site ◽  
Sts Markers ◽  
Advance Regeneration ◽  
Spruce Stands ◽  
Fixation Indices ◽  
Fire Origin

cDNA-based sequence-tagged-site (STS) markers were used to examine the genetic composition of three mature, layer-origin populations of black spruce (Picea mariana (Mill.) BSP), which were the result of logging operations in the first half of the 20th century, and compare them with four mature, seedling-origin populations that regenerated naturally following fire. The amount of STS-marker variation revealed in these populations was very similar to that previously observed in a rangewide panel of black spruce trees. There was little differentiation among populations, and no significant differences in heterozygosities, numbers of alleles, or fixation indices were evident between layer-origin and fire-origin stands. Likewise, when mating-system parameters were estimated in one population of each of these two types, no significant differences were found; outcrossing was essentially complete with no evidence of mating among relatives. The estimated correlation of paternity within progeny arrays was about 17 and 13% in the fire-origin and layer-origin stands, respectively, but again the observed difference was not statistically significant. At least at the current scale of sampling, silvicultural practices that result in stand replacement by layer-origin advance regeneration appear not to have had negative impact upon the genetic diversity or level of inbreeding in second-growth black spruce stands.

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