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Biochemical Genetics (v.44, #1-2)
Extensive Natural Hybridization Between Two Geckos, Gekko tawaensis and Gekko japonicus (Reptilia: Squamata), Throughout Their Broad Sympatric Area by Mamoru Toda; Sumio Okada; Tsutomu Hikida; Hidetoshi Ota (pp. 1-17).
The status of natural hybridization between the two Japanese geckos, Gekko tawaensis and Gekko japonicus, was surveyed by use of 15 diagnostic allozyme loci. Of 438 specimens examined, 9 were identified as Fl, 1 was a first backcross with G. japonicus, and 15 were identified as more successive generations. Hybridizations were detected at 7 of the 15 localities interspersed throughout a broad sympatric area of the two species, forming a mosaic hybrid zone. A comparison of species–hybrid composition between 2-year samples from a single locality and a 5-year interval showed no evidence for progressive introgression or establishment of a hybrid swarm, despite constant emergences of Fl hybrids. Nonprevalence of the hybrid genotypes was also indicated by the analysis using hybrid index scores for all other localities examined. These results suggest that strong selection acts against hybrid genotypes. Morphological features of hybrid individuals were also provided.
Keywords: natural hybridization; Gekko ; hybrid index; introgression; allozyme
Genetic Relationship of Chinese and Japanese Gamecocks Revealed by mtDNA Sequence Variation by Yi-Ping Liu; Qing Zhu; Yong-Gang Yao (pp. 18-28).
Cockfighting has a very long history dating back to as early as 2500 years ago in China. Cockfighting was intertwined with human cultural traditions, helped disperse chickens across the world, and influenced the subsequent breed selection. Therefore, tracing the origin of gamecocks could mirror the distribution of the cockfighting culture. In this study, we compared the available mtDNA control region sequences in Chinese and Japanese gamecocks to test the recently proposed hypothesis behind the dual origin of the Japanese cockfighting culture (from China and Southeast Asia independently). We assigned gamecock mtDNAs to different matrilineal components (or phylogenetic clades) that emerged from the phylogenetic tree and network profile, and compared the frequency differences between Chinese and Japanese gamecocks. Among the six clades (A–F) identified, Japanese gamecocks were most frequently found in clades C and D (74%, 32/43), whereas more than half of the Chinese gamecock samples (69%, 35/51) were grouped in clades A and B. Haplotypes in Japanese gamecocks assigned to clades A, B, and E were either shared with those of the Chinese samples or differed from the close Chinese types by no more than a three-mutation distance. This genetic pattern is in accordance with the proposed dual origin of Japanese gamecocks but has left room for single origin of Japanese gamecocks from China. The genetic structure of gamecocks in China and Japan might also be influenced by subsequent breed selection and conservation after the initial gamecock introduction.
Keywords: Mitochondrial DNA; gamecock; origin; Douji; Shamo
A Study of Conservation Genetics in Cupressus chengiana, an Endangered Endemic of China, Using ISSR Markers by Bingqing Hao; Wang Li; Mu Linchun; Yao Li; Zhang Rui; Tang Mingxia; Bao Weikai (pp. 29-43).
ISSR markers were used to analyze the genetic diversity and genetic structure of eight natural populations of Cupressus chengiana in China. ISSR analysis using 10 primers was carried out on 92 different samples. At the species level, 136 polymorphic loci were detected. The percentage of polymorphic bands (PPB) was 99%. Genetic diversity (H e) was 0.3120, effective number of alleles (A e) was 1.5236, and Shannon’s information index (I) was 0.4740. At the population level, PPB = 48%, A e=1.2774, H e=0.1631, and I=0.2452. Genetic differentiation (G st) detected by Nei’s genetic diversity analysis suggested 48% occurred among populations. The partitioning of molecular variance by AMOVA analysis indicated significant genetic differentiation within populations (54%) and among populations (46%; P < 0.0003). The average number of individuals exchanged between populations per generation (N m ) was 0.5436. Samples from the same population clustered in the same population-specific cluster, and two groups of Sichuan and Gansu populations were distinguishable. A significantly positive correlation between genetic and geographic distance was detected (r=0.6701). Human impacts were considered one of the main factors to cause the rarity of C. chengiana, and conservation strategies are suggested based on the genetic characters and field investigation, e.g., protection of wild populations, reestablishment of germplasm bank, and reintroduction of more genetic diversity.
Keywords: Cupressus chengiana ; ISSR; genetic diversity; genetic structure; differentiation
AFLP Analysis of Genetic Diversity of the Endangered Species Sinopodophyllum hexandrum in the Tibetan Region of Sichuan Province, China by Meng Xiao; Qun Li; Liang Guo; Tong Luo; Wen-Xia Duan; Wen-Xing He; Li Wang; Fang Chen (pp. 44-57).
Amplified fragment length polymorphism (AFLP) markers were used to estimate the genetic diversity of seven wild populations of Sinopodophyllum hexandrum (Royle) Ying from the Tibetan region of Sichuan Province, China. Six primer combinations generated a total of 428 discernible DNA fragments, of which 111 were polymorphic. The percentage of polymorphic bands (PPB) was 25.93 at the species level, and PPB within population ranged from 4.91 to 12.38%. Genetic diversity (H E) within populations varied from 0.01 to 0.04, averaging 0.05 at the species level. As revealed by the results of AMOVA analysis, 58.8% of the genetic differentiation occurred between populations, and 41.2% within populations. The genetic differentiation was, perhaps, due to the limited gene flow (N m=0.43) of the species. The correlation coefficient (r) between genetic and geographical distance using Mantel's test for all populations was 0.698 (P=0.014). The UPGMA cluster analysis revealed a similar result in that the genetic distances among the populations show, to a certain extent, a spatial pattern corresponding to their geographic locations. On the basis of the genetic and ecological information, we propose some appropriate strategies for conserving the endangered S. hexandrum in this region.
Keywords: Sinopodophyllum hexandrum ; amplified fragment length polymorphism (AFLP); genetic diversity; conservation
Digestion of I-PpoI Recognition Sites in Unfavorable Sequence Contexts Achieved by Changing the Reaction Conditions
by Christina B. McCarthy; Victor Romanowski (pp. 58-65).
Cloning and Characterization of a Novel Human Prefoldin and SPEC Domain Protein Gene (PFD6L) From the Fetal Brain
by Jiayi Zhang; Lingfeng Liu; Xiaomeng Zhang; Feng Jin; Jinzhong Chen; Chaoneng Ji; Shaohua Gu; Yi Xie; Yumin Mao (pp. 66-71).
Molecular Identification of Tropical Tasar Silkworm (Antheraea mylitta) Ecoraces with RAPD and SCAR Markers by Monalee Saha; S. C. Kundu (pp. 72-85).
The tropical tasar silkworm, Antheraea mylitta, has several ecoraces, 10 of which are commercially exploited for the production of tasar silk. These ecoraces are identified by morphological markers that are greatly influenced by photoperiod, humidity, altitude, and host plants. The DNA markers, random amplification of polymorphic DNA (RAPD), and sequence-characterized amplified region (SCAR) are identified to complement the existing morphological markers. Seven RAPD bands are selected that identify 8 of the 10 ecoraces. These identified RAPD fragments are sequenced and primers are designed for SCAR markers. Of the seven sets of primers, a single primer pair produced polymorphic SCAR bands that diagnose 5 of the 10 ecoraces. All 10 ecoraces are identified by the use of RAPD and SCAR markers together.
Keywords: Antheraea mylitta ; tasar silkworm; ecoraces; random amplification of polymorphic DNA; sequence-characterized amplified regions