Golda Meir with family

Golda Meir with her children, her son-in-law, and her grandchildren.Grayscal

Study site and <i>A</i>. <i>tortilis</i> distributions.

<p><b>a</b>: map of subpopulation sampling site distribution in Israel and Jordan. Also shown are the major drainage basins across the study area. <b>b</b>: acacia gazelles (<i>Gazella gazella acaciae</i> = <i>G</i>.<i>g</i>. <i>cora</i>) feeding on the foliage of <i>Acacia tortilis</i> at Yotveta Nature Reserve, Israel. Photo: Benny Shalmon. <b>c</b>: the location of the two sites from the species’ central distribution in Sudan and Egypt (black trees; map adapted from <a href="http://www.bjdesign.com" target="_blank">www.bjdesign.com</a>). <b>d</b>: the approximate distribution of <i>A</i>. <i>tortilis</i>. This map is similar but not identical to a map published by FAO (<a href="http://www.fao.org/docrep/006/Q2934E/Q2934E05.htm" target="_blank">http://www.fao.org/docrep/006/Q2934E/Q2934E05.htm</a>), and is therefore for illustrative purposes only.</p

Study site locations and associated genetic diversity and centrality measures.

<p>Study site locations and associated genetic diversity and centrality measures.</p

Detecting hierarchical levels of connectivity in a population of <i>Acacia tortilis</i> at the northern edge of the species’ global distribution: Combining classical population genetics and network analyses

<div><p>Genetic diversity and structure of populations at the edge of the species’ spatial distribution are important for potential adaptation to environmental changes and consequently, for the long-term survival of the species. Here, we combined classical population genetic methods with newly developed network analyses to gain complementary insights into the genetic structure and diversity of <i>Acacia tortilis</i>, a keystone desert tree, at the northern edge of its global distribution, where the population is under threat from climatic, ecological, and anthropogenic changes. We sampled <i>A</i>. <i>tortilis</i> from 14 sites along the Dead Sea region and the Arava Valley in Israel and in Jordan. In addition, we obtained samples from Egypt and Sudan, the hypothesized origin of the species. Samples from all sites were genotyped using six polymorphic microsatellite loci.Our results indicate a significant genetic structure in <i>A</i>. <i>tortilis</i> along the Arava Valley. This was detected at different hierarchical levels—from the basic unit of the subpopulation, corresponding to groups of trees within ephemeral rivers (wadis), to groups of subpopulations (<i>communities</i>) that are genetically more connected relative to others. The latter structure mostly corresponds to the partition of the major drainage basins in the area. Network analyses, combined with classical methods, allowed for the identification of key <i>A</i>. <i>tortilis</i> subpopulations in this region, characterized by their relatively high level of genetic diversity and centrality in maintaining gene flow in the population. Characterizing such key subpopulations may enable conservation managers to focus their efforts on certain subpopulations that might be particularly important for the population’s long-term persistence, thus contributing to species conservation within its peripheral range.</p></div

The genetic networks obtained from POPGRAPH.

<p>Shown are networks for all subpopulations in Israel and Jordan with node size representing within-site genetic diversity as <b>a</b>. observed heterozygosity and <b>b</b>. allelic richness. Node color shade represents the degree of RWB centrality, with darker color indicating a higher degree. <b>c</b>. Community structure in the genetic network of the <i>A</i>. <i>tortilis</i> tree population in Israel and Jordan, as determined by spectral-decomposition community detection [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0194901#pone.0194901.ref018" target="_blank">18</a>]. Different node colors indicate membership in different communities detected by the algorithm. Node size represents genetic diversity as measured by the observed heterozygosity.</p