Genetic diversity in Guazuma crinita from eleven provenances in the Peruvian Amazon revealed by ISSR markers

Abstract

SUMMARYGuazuma crinita is an important fast-growing timber tree species widely used in agroforestry systems in the Peruvian Amazon. The objectives of our research were (i) to assess genetic diversity of G. crinita using inter-simple sequence repeat (ISSR) markers and (ii) estimate correlation between genetic and geographic distances among provenances. The sample included 44 genotypes from 11 provenances in the Aguaytia and neighboring Pachitea watersheds in the Peruvian Amazon. Ten ISSR primers amplified a total of 65 bands of which 61 were polymorphic (93.8 %). The range of DNA amplification varied from 260 to 2,200 bp. Among the provenances, Macuya exhibited the highest percentage of polymorphic bands (PPB) with 67.7 %, 0.21 Nei's gene diversity (He) and 0.33 Shannon index (I). Overall genetic differentiation (G st ) was 0.03, indicating 97 % of genetic diversity within provenances. Gene flow (Nm) was 12.9 alleles per generation. Cluster analysis was not related to geographic origin, suggesting a common gene pool. However a weak positive correlation (r = 0.27, P < 0.05) was found between genetic and geographic distance. This is the first study of genetic diversity and structure of G. crinita. We recommend in situ conservation strategies for populations with high levels of genetic diversity.Key words: inter-simple sequence repeat markers, genetic diversity, genetic distance, gene flow, geographic distance. RESUMENGuazuma crinita es una importante especie maderable de rápido crecimiento ampliamente usada en sistemas agroforestales en la Amazonía Peruana. Los objetivos de nuestra investigación fueron; (i) evaluar la diversidad genética de G. crinita revelada por marcadores de intersecuencias simples repetidas (ISSR) además de (ii) estimar la correlación entre las distancias genéticas y geográficas entre procedencias. La muestra incluyó 44 genotipos de 11 procedencias en las cuencas de Aguaytía y Pachitea en la Amazonía Peruana. Diez cebadores ISSR amplificaron un total de 65 bandas de las cuales 61 fueron polimórficas (93,8 %). El rango de amplificaciones de ADN varió desde 260 hasta 2.200 bp. Entre las procedencias, Macuya exhibió el mayor porcentaje de bandas polimórficas (PPB) con 67,7 %, 0,21 diversidad genética de Nei (He) y 0,33 de índice de Shannon (I). La diferenciación genética general (G st ) fue 0,03, indicando 97 % de la variación genética dentro de las procedencias. El flujo genético (Nm) fue 12,9 alelos por generación. El análisis de agrupamiento no estuvo relacionado con el origen geográfico sugiriendo una fuente genética en común. Sin embargo, se encontró una correlación positiva débil (r = 0,27, P < 0,05) entre las distancias genéticas y geográficas. Este es el primer estudio sobre la diversidad y estructura genética de G. crinita. Se recomiendan estrategias de conservación in situ para las poblaciones con altos niveles de diversidad genética.Palabras clave: marcadores Inter-simple sequence repeat, diversidad genética, distancia genética, flujo genético, distancia geográfica.

Preliminary Evidence for Domestication Effects on the Genetic Diversity of Guazuma crinita in the Peruvian Amazon

“…The sample size in this study was small so we consider the results as preliminary. Other studies of genetic diversity in tropical tree species have also used small sample sizes [17,[19][20][21][22] and reported genetic diversity patterns consistent with studies based on large sample sizes.…”

“…This research assesses genetic diversity in G. crinita based on amplified fragment length polymorphism (AFLP) markers, and we found 99.4% polymorphism. In another study involving eleven provenances of G. crinita in the Peruvian Amazon, there was 93.8% polymorphism based on Inter Simple Sequence Repeat (ISSR) [17]. Although the methods were different, both studies confirm high levels of genetic diversity in G. crinita.…”

“…crinita is a cross pollinated species that produces fruit at an early age, and can potentially disperse seeds over a long distance by both wind and water, allowing it to colonize forest gaps and potentially form dense stands of natural regeneration [14]. These dispersal characteristics should produce extensive gene flow among populations, resulting in high levels of genetic diversity within population and relatively low genetic differentiation among populations [15][16][17]. Local farmers manage G. crinita in its natural ecological niche for timber, while also engaging in other agricultural activities.…”

Outcrossing Rate and Genetic Variability in Mexican Race Avocado

“…Total nHe was 0.482 and ranged from 0.478 to 0.511 for families 'Criollo 3' and 'Pl atano Delgado', respectively. These results showed a low genetic variability within avocado families and also demonstrated that ISSR markers are an efficient tool to identify genotypes, even among closely related individuals and a rather small sample size (Thangjam, 2014;Tuisima et al, 2016). According to Nei (1978), the number of individuals for estimating genetic distance can be very small (#10) if the number of loci is more than 50, or if the genetic distance is large, and the average heterozygosity of the two species compared is low.…”

Research Article Analysis of genetic diversity of Hyptis pectinata (L.) Poit. plants using ISSR markers.

“…Molecular markers have been the most frequent strategy used to analyze such variability. The inter-simple sequence repeat (ISSR) markers are advantageous owing to their high reproducibility and low costs; moreover, they do not require prior knowledge of DNA sequences for the development of specific primers of the species under analysis (Coral et al, 2016).…”