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Genetic linkage maps of the guppy ( Poecilia reticulata) were constructed from independent crosses between the Tuxedo strain and a feral line (Wildtype). Segregation patterns of random amplified polymorphic DNA (RAPD) markers and phenotypic markers were investigated in F(2) offspring of Tuxedo male symbol male symbol x Wildtype female symbol female symbol and Wildtype male symbol male symbol x Tuxedo female symbol female symbol crosses. Among the 300 and 276 RAPD markers scored for the respective crosses, linkages were identified for 230 and 212, respectively. The Tuxedo male symbol male symbol x Wildtype female symbol female symbol and Wildtype male symbol male symbol x Tuxedo female symbol female symbol maps spanned 2100 Kosambi centiMorgans (cM(K)) and 1900 cM(K), respectively, in 28 linkage groups. Average marker resolution was 10 cM(K). Genome length was estimated at 4410 cM(K) and 4060 cM(K) for the respective crosses, with an average physical distance of 166 kbp/cM(K). Several RAPD markers were closely linked to or mapped onto the loci for the sex-determining region (SdR), and the sex-linked black caudal-peduncle ( Bcp) and red tail ( Rdt) genes. These primary linkage maps are the initial step toward the construction of a composite high-density map to facilitate map-based cloning and marker-assisted selection of quantitative trait loci that are essential for the development of comprehensive breeding programs for the guppy.

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We have employed a semiempirical molecular-orbital method to simulate the adsorption of chlorine (Cl) atoms on GaAs(110) for three cases: monatomic Cl, molecular Cl, and 0.16-monolayer (ML) coverage of Cl. For the single Cl atom, the equilibrium bonding site has the Cl atom at the on-top site of the surface As atom. The C12 molecule on GaAs(110) displays dissociative adsorption with both Cl-Ga and Cl-As bonding configurations. For the third case, Cl adsorption on GaAs(110) leads to enhanced relaxation beyond that of the already relaxed surface. In this geometry, the surface As atoms gain charge at the expense of the surface Ga atoms and are pushed further away from the surface plane while the Ga atoms relax inward. The microscopic structure of 0.16-ML coverage of Cl displays both Ga-Cl and As-Cl bonding configurations. For the Ga-Cl bonding configuration, the Cl atom is adsorbed at the surface Ga dangling-bond site while for As-Cl, the Cl atom is sited atop the surface As atom, ofFset slightly toward the dangling-bond direction. The Cl adsorbed at the Ga site is lower in height than Cl atop the surface As atom relative to the substrate and the Cl-C1 nearest-neighbor distance calculated is 3.60 A, 0 quite close to the value of 3.46 A observed experimentally with the scanning tunneling microscope (STM). These results compare favorably with the findings of Stepniak, Rioux, and Weaver from recent photoelectron spectroscopy experiments, as well as the structural information obtained from STM.

Ng CKC, Ooi PAC, Wong WL, Khoo G. 2018. Ichthyofauna checklist (Chordata: Actinopterygii) for indicating water quality in Kampar River catchment, Malaysia. Biodiversitas 19: 2252-2274. The limnological habitats are receptors of pollution, thus local fish species richness is a plausible biological indicator to reflect the quality of a particular water body. However, database on species occurrence that corresponds with the water physico-chemistry constituents is often not available. The problem is compounded by the lack of species identification description to assist those working on river and freshwater resource conservation projects. This paper attempts to fill the gaps in the context of Kampar River drainage. Based on sampling exercises conducted from October 2015 to March 2017, an annotated list with visual data for 56 species belonging to 44 genera and 23 families is presented. The water physico-chemistry data is also summarized with the corresponding visual data of limnological zones studied. The species diversity results are further compared with other local drainages and the correlation between area size and their relationship is expressed by y = 17.627e0.0601x. This paper provides species-level identification information for front line practice and demonstrates how the fish taxonomy discipline can be adapted for practical application in freshwater resource monitoring and management.