A total 23 morphological traits, 19 AFLP-primer combinations, 80 RAPD primers and 32 SSR primer pair were used to compare the informativeness and efficiency of random amplified polymorphic DNA （RAPD）, amplified frag...A total 23 morphological traits, 19 AFLP-primer combinations, 80 RAPD primers and 32 SSR primer pair were used to compare the informativeness and efficiency of random amplified polymorphic DNA （RAPD）, amplified fragment length polymorphism （AFLP） and simple sequence repeat （SSR） markers in establishing genetic relationships among 29 almond cultivars and three related wild species. SSRs presented a high level of polymorphism and greater information content, as assessed by the expected hetrozygosity, compared to AFLPs and RAPDs. The lowest values of expected hetrozygosity were obtained for AFLPs; however AFLPs showed the highest efficiency, owing to their capacity to reveal large numbers of bands per reaction, which led to high values for various types of indices of diversity. All the three techniques discriminated almond genotypes very effectively, except that SSRs failed to discriminate between ＇Monagha＇ and ＇Sefied＇ almond genotypes. The correlation coefficients of similarity were statistically significant for all the three marker systems, but were lower for the SSR data than for RAPDs and AFLPs. For all the markers, high similarity in dendrogram topologies was obtained, although some differences were observed. All the dendrograms, including that obtained by the combined use of all the marker data, reflect relationships for most of cultivars according to their geographic diffusion. AMOVA detected more variation among cultivated and related wild species of almond within each geographic group. Bootstrap analysis revealed that the number of markers used was sufficient for reliable estimation of genetic similarity and for meaningful comparisons of marker types.展开更多
Huangguogan, an obvious Citrus hybrid, is suitable for transportation and export and ripens in March or April. Because of late season, it may playa significant role in fruit market. However, its origin is still unconf...Huangguogan, an obvious Citrus hybrid, is suitable for transportation and export and ripens in March or April. Because of late season, it may playa significant role in fruit market. However, its origin is still unconfirmed. The aim of this study was to clarify the possible parentage of Huangguogan via the combination of morphological and molecular markers including simple sequence repeat （SSR） and chloroplast simple sequence repeat （cpSSR）. Analysis of morphological traits including leaf stalk length, phylliform index and fruit shape index indicated that Huangguogan had similarities in morphology with Sweet orange. The SSR Cluster Analysis showed that Huangguogan was clustered together with Hongju tangerine and revealed -80% genetic similarity. They illustrated a close genetic distance between Huangguogan and Hongju tangerine. In addition, the bands of2 polymorphic cpSSR were identical in Huangguoggan and Sweet orange. Consequently, it is likely that its female parentage was the sweet orange （Citrus sinensis （L.） Osbeck） and its male parentage was the tangerine （Citrus reticulata Blanco）.展开更多
Speciation research has seen a renewed interest in ecological speciation, which emphasises divergent ecological se- lection leading to the evolution of reproductive isolation. Selection from divergent ecologies means ...Speciation research has seen a renewed interest in ecological speciation, which emphasises divergent ecological se- lection leading to the evolution of reproductive isolation. Selection from divergent ecologies means that phenotypic plasticity can play an important role in ecological speciation. Phenotypic plasticity involves the induction of phenotypes over the lifetime of an organism and emerging evidence suggests that epigenetic marks such as cytosine and protein （histone） modifications might regu- late such environmental induction. Epigenetic marks play a wide role in a variety of processes including development, sex dif- ferentiation and allocation, sexual conflict, regulation of transposable elements and phenotypic plasticity. Here we describe recent studies that investigate epigenetic mechanisms in a variety of contexts. There is mounting evidence for environmentally induced epigenetic variation and for the stable inheritance of epigenetic marks between generations. Thus, epigenetically-based pheno- typic plasticity may play a role in adaptation and ecological speciation. However, there is less evidence for the inheritance of in- duced epigenetic variation across multiple generations in animals. Currently few studies of ecological speciation incorporate the potential for the involvement of epigenetically-based induction of phenotypes, and we argue that this is an important omission [Current Zoology 59 （5）： 686-696, 2013 ].展开更多
文摘A total 23 morphological traits, 19 AFLP-primer combinations, 80 RAPD primers and 32 SSR primer pair were used to compare the informativeness and efficiency of random amplified polymorphic DNA （RAPD）, amplified fragment length polymorphism （AFLP） and simple sequence repeat （SSR） markers in establishing genetic relationships among 29 almond cultivars and three related wild species. SSRs presented a high level of polymorphism and greater information content, as assessed by the expected hetrozygosity, compared to AFLPs and RAPDs. The lowest values of expected hetrozygosity were obtained for AFLPs; however AFLPs showed the highest efficiency, owing to their capacity to reveal large numbers of bands per reaction, which led to high values for various types of indices of diversity. All the three techniques discriminated almond genotypes very effectively, except that SSRs failed to discriminate between ＇Monagha＇ and ＇Sefied＇ almond genotypes. The correlation coefficients of similarity were statistically significant for all the three marker systems, but were lower for the SSR data than for RAPDs and AFLPs. For all the markers, high similarity in dendrogram topologies was obtained, although some differences were observed. All the dendrograms, including that obtained by the combined use of all the marker data, reflect relationships for most of cultivars according to their geographic diffusion. AMOVA detected more variation among cultivated and related wild species of almond within each geographic group. Bootstrap analysis revealed that the number of markers used was sufficient for reliable estimation of genetic similarity and for meaningful comparisons of marker types.
文摘Huangguogan, an obvious Citrus hybrid, is suitable for transportation and export and ripens in March or April. Because of late season, it may playa significant role in fruit market. However, its origin is still unconfirmed. The aim of this study was to clarify the possible parentage of Huangguogan via the combination of morphological and molecular markers including simple sequence repeat （SSR） and chloroplast simple sequence repeat （cpSSR）. Analysis of morphological traits including leaf stalk length, phylliform index and fruit shape index indicated that Huangguogan had similarities in morphology with Sweet orange. The SSR Cluster Analysis showed that Huangguogan was clustered together with Hongju tangerine and revealed -80% genetic similarity. They illustrated a close genetic distance between Huangguogan and Hongju tangerine. In addition, the bands of2 polymorphic cpSSR were identical in Huangguoggan and Sweet orange. Consequently, it is likely that its female parentage was the sweet orange （Citrus sinensis （L.） Osbeck） and its male parentage was the tangerine （Citrus reticulata Blanco）.
文摘Speciation research has seen a renewed interest in ecological speciation, which emphasises divergent ecological se- lection leading to the evolution of reproductive isolation. Selection from divergent ecologies means that phenotypic plasticity can play an important role in ecological speciation. Phenotypic plasticity involves the induction of phenotypes over the lifetime of an organism and emerging evidence suggests that epigenetic marks such as cytosine and protein （histone） modifications might regu- late such environmental induction. Epigenetic marks play a wide role in a variety of processes including development, sex dif- ferentiation and allocation, sexual conflict, regulation of transposable elements and phenotypic plasticity. Here we describe recent studies that investigate epigenetic mechanisms in a variety of contexts. There is mounting evidence for environmentally induced epigenetic variation and for the stable inheritance of epigenetic marks between generations. Thus, epigenetically-based pheno- typic plasticity may play a role in adaptation and ecological speciation. However, there is less evidence for the inheritance of in- duced epigenetic variation across multiple generations in animals. Currently few studies of ecological speciation incorporate the potential for the involvement of epigenetically-based induction of phenotypes, and we argue that this is an important omission [Current Zoology 59 （5）： 686-696, 2013 ].
