Development and characterization of novel microsatellite markers for Ginkgo biloba using 454 pyrosequencing.

As a "living fossil" that is used to understand the evolutionary history of seed plants, Ginkgo biloba is a well-known multipurpose tree with edible seeds, medicinal properties, and ornamental value, but little is known about its genetic diversity. Microsatellite, or simple sequence repeat (SSR), markers have proven to be powerful tools for genetic studies of plants. In this study, we isolated 30 novel polymorphic microsatellite loci in G. biloba using 454 pyrosequencing. The characteristics of these loci were tested with 48 cultivars. The number of alleles (NA) per locus ranged from two to seven. The observed (HO) and expected (HE) heterozygosities ranged from 0.000 to 0.750 and from 0.021 to 0.792, with an average of 0.326 and 0.443, respectively. In terms of genetic diversity in the Ginkgo population, NA was 3.300, NE was 2.090, I was 0.782, HO was 0.326, and HE was 0.443. These polymorphic SSRs will be useful for the assessment of population genetic diversity and resource conservation of G. biloba.

Development of novel chloroplast microsatellite markers for Ginkgo biloba.

Ginkgo biloba is considered to be a living fossil that can be used to understand the ancient evolutionary history of gymnosperms, but little attention has been given to the study of its population genetics, molecular phylogeography, and genetic resources assessment. Chloroplast simple sequence repeat (cpSSR) markers are powerful tools for genetic studies of plants. In this study, a total of 30 perfect cpSSRs of Ginkgo were identified and characterized, including di-, tri, tetra-, penta-, and hexanucleotide repeats. Fifteen of 21 designed primer pairs were successfully amplified to yield specific polymerase chain reaction products from 16 Ginkgo cultivars. Polymorphic cpSSRs were further applied to determine the genetic variation of 116 individuals in 5 populations of G. biloba. The results showed that 24 and 76% genetic variation existed within and among populations of this species, respectively. These polymorphic and monomorphic cpSSR markers can be used to trace the origin and evolutionary history of Ginkgo.