Pollen gene flow and molecular identification of full-sib families in small and isolated population fragments ofGleditsia triacanthosL.

Abstract

To analyze the utility of isolated remnant populations for full-sibling (full-sib) identification among open-pollinated single-tree progeny in the outcrossing and insect-pollinated tree Gleditsia triacanthos L. (honey locust), we performed paternity analyses in forest fragments from two geographic regions using nuclear microsatellites. The first plot (Butternut Valley population) comprised only 7 trees, and 552 seedlings from a single seed parent were characterized at nuclear microsatellites. A large number of putative pollen donors (59) were identified in kinship analyses, but their individual contributions to the progeny were highly variable. Kinship and paternity analyses identified 149 putative full-sibs for genetic mapping sired by an external (unsampled) pollen parent. To better assess the frequency of long-distance pollen dispersal, a total of 180 seeds were collected from 6 seed parents in another fragmented population. In both plots, contemporary pollen dispersal occurred generally from outside the plots (99.38% and 87.50%–100% at the Butternut Valley and Ames Plantation sites, respectively) and thus over very long distances (>12 000 m in the Ames Plantation) suggesting that in highly fragmented landscapes, insect pollinators of honey locust are likely very effective long-distance dispersers.

Endangered but genetically stable—Erythrophleum fordii within Feng Shui woodlands in suburbanized villages

“…However, empirical evidence does not always support this in other disturbed habitats (Giombini, Bravo, Sica, & Tosto, ; Noreen, Niissalo, Lum, & Webb, ; Rosas, Quesada, Lobo, & Sork, ). Therefore, the genetic consequences for a small population or due habitat disturbance are both species and location specific (Owusu, Schlarbaum, Carlson, & Cailing, ; Schwarcz et al, ). In particular, we also examined the demographic history of Feng Shui populations of E. fordii to study how the current level genetic diversity is related to historical events such as bottlenecks.…”

Development of genic and genomic microsatellites in Gleditsia triacanthos L. (Fabaceae) using Illumina sequencing

“…For genomic SSRs, a total of 4715 primer pairs flanking SSR motifs were identified and 14 polymorphic SSRs were developed earlier (Owusu et al 2013). However, testing of these markers in different single-tree progenies revealed null alleles for eight of these markers in some progenies limiting the application for gene flow analyses (Owusu et al 2016). In the present study we describe the development of additional 33 polymorphic markers (20 EST-SSRs, 13 genomic SSRs).…”

“…The new genomic and EST-SSRs can be used for the assessment of genetic variation and for gene flow analyses in honeylocust (Owusu et al 2016). Additionally, genetic characterization at these markers can be performed in populations from contrasting environments or along environmental gradients to test for selective neutrality of markers.…”

“…All of these markers were applicable for genetic variation assessments in a reference panel of 36 samples collected from a provenance trial (Owusu et al 2013). However, due to signatures of null alleles in some seed parents, only six to nine of these markers were used for gene flow analyses in honeylocust population fragments (Owusu et al 2016). …”

“…As part of the Hardwood Genomics project (http://www.hardwoodgenomics.org/) we are developing genome/transcriptome resources and genetic linkage maps in eastern North American hardwood species from different taxonomic orders. For honeylocust, we have developed genomic SSRs (Owusu et al 2013) for genetic variation and gene flow analyses (Owusu et al 2016) and a framework genetic linkage map for Quantitative Trait Locus (QTL) and comparative mapping based on restriction site associated sequencing (RAD-seq) markers (Gailing et al 2017). …”