Genetic diversity and structure of native and non-native populations of the endangered plant Pinus dabeshanensis.

Owing to a severe decline in its abundance, Pinus dabeshanensis has been listed as an endangered species by the International Union for the Conservation of Nature. Although several restoration events have been undertaken since the 1960s, the natural population genetic structure of this species remains to be investigated. Herein, we examined the level of genetic diversity and structure of two native and two non-native populations using 10 microsatellite loci. A relatively high level of genetic variation (HO = 0.586 ± 0.039) and a low level of population differentiation (FST = 0.016 ± 0.011) were revealed. For forensic investigation, an assignment test was performed. To better understand the genetic differentiation between the native and non-native populations, the individuals in the transplanted and cultivated populations may have derived from populations that were not surveyed in this study. In light of our results, we discuss the real problems faced by all four populations and provide useful information for management decision-making.

NF1 frameshift mutation (c.6520_6523delGAGA) association with nervous system tumors and bone abnormalities in a Chinese patient with neurofibromatosis type 1.

Neurofibromatosis type 1, also known as NF1 or von Recklinghausen's disease, is a common neurocutaneous syndrome that presents with multiple café-au-lait patches, skinfold freckling, dermatofibromas, neurofibromas, and Lisch nodules. The mutations of the gene NF1, encoding the protein neurofibromin, have been identified as the cause of this disease. Here, we report a clinical and molecular study of a Chinese patient with multiple café-au-lait skin freckles, dermatofibroma, central and peripheral nervous system tumors, and bone abnormalities attributed to NF1. The patient showed >6 café-au-lait spots on the body and multiple dermatofibromas. A brain glioma and multiple nerve sheath tumors inside and outside the vertebral canal were identified by magnetic resonance imaging, which also showed multiple intercostal nerve schwannomas and hydrocephalies above the cerebellar tentorium. Talipes equinus was also apparent. A mutation analysis of the NF1 gene revealed a novel frameshift mutation in exon 43, consisting of a heterozygous deletion of four nucleotides (GAGA) between positions 6520 and 6523. No NF1 mutations were detected in the patient's parents or younger brother. These results extend the list of known mutations in this gene. The absence of the NF1 mutation in the healthy family members suggests that it is responsible for the NF1 phenotype. To our knowledge, this frameshift mutation represents a novel NF1 case, and may be associated with nervous system tumors and bone abnormalities.

Development and characterization of new microsatellites for walnut (Juglans regia).

The expressed sequence tag (EST) database represents a potentially valuable resource for the development of simple sequence repeat (SSR) markers for use in evolutionary studies. EST-SSRs reveal polymorphisms not only within the source taxon, but in related taxa as well. In this paper, we describe a case study in which the publicly available walnut (Juglans regia) EST database was used to develop SSR markers for use in the genetic analysis of the widespread Juglans nigra and Carya cathayensis and an endangered species Annamocarya sinensis. A total of 7262 unigenes, including 1911 contigs and 5351 singletons, were obtained from 13,559 ESTs retrieved from the NCBI database. The 7262 unigenes were further reduced to 706 EST-SSR sequences containing 805 SSR loci. Then, 309 EST-SSR primers were randomly designed, and 77 were identified with five high across-species transferability cross-species: namely, J. regia, J. nigra, C. cathayensis, Carya dabieshanensis, and A. sinensis. Thirteen highly polymorphic EST-SSRs were further used for genetic analyses in these above five species.

Conservation genetics of Annamocarya sinensis (Dode) Leroy, an endangered endemic species.

The endangered perennial plant Annamocarya sinensis (Dode) Leroy is a tertiary relict tree restricted to southeastern China and northern Vietnam. To explore endangerment mechanisms, develop protection strategies, and guide reintroduction efforts for this species, we investigated genetic diversity and population structure by surveying 70 individuals from three distinct populations using 12 polymorphic microsatellite markers. We found high genetic diversity for A. sinensis as indicated by high allelic diversity (allelic number = 4.667 ± 0.436, effective number of alleles = 2.913 ± 0.249), excess heterozygosity (observed heterozygosity = 0.586 ± 0.039, expected heterozygosity = 0.582 ± 0.029), and low fixation index (-0.028 ± 0.057). Our research revealed low genetic differentiation (FST = 0.066 ± 0.011) and no correlation between genetic distance and geographic distance. Analysis of molecular variance attributed 87% of the variance to differences within the population, whereas 13% was distributed among populations. The protection strategy should aim to protect as many populations as possible. Promoting sexual reproduction among various genotypes and establishing an outcrossing program are advisable for A. sinensis.