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Abstract--Molecular-based approaches for shark species identification have been driven largely by issues specific to the fishery. In an effort to establish a more comprehensive identification data set, we investigated DNA [...]

Invasive species threaten native taxa with extirpation and extinction via several biological mechanisms. One such mechanism, hybridization and subsequent introgression of invasive alleles into native genomes is a serious concern, especially for taxa displaying weak reproductive barriers, as is the case for black basses. Black basses introduced outside of their native ranges thus pose elevated threats to endemic congeners, particularly in the southern United States where restricted ranges preclude refuge from introgression. The recently delineated Bartram's bass ( M. sp. cf M. coosae) is endemic to the upper regions of the Savannah River basin, throughout which anthropogenic modification, including impoundment, has been extensive. Non-native Alabama bass ( M. henshalli) and smallmouth bass ( M. dolomieu) have been introduced into this system on multiple occasions and now threaten Bartram's bass via introgression. In this study we sampled four reservoirs (Jocassee, Keowee, Hartwell, and Russell) in the upper Savannah River during 2004 and 2010. Results from three codominant nuclear loci and one mitochondrial locus revealed extensive introgression between Alabama and Bartram's bass. Results show that Alabama bass have replaced Bartram's bass in lakes Keowee and Russell, where they were first introduced, while the frequencies of hybrids in lakes Jocassee and Hartwell are increasing. Hybridization involving Bartram's bass with native largemouth bass and introduced smallmouth bass was detected in very low frequencies. Results highlight the importance of continual study over geographic and temporal scales to inform management and conservation of rare fishes threatened with extinction via interspecific hybridization. [ABSTRACT FROM AUTHOR]

The article focuses on the use of DNA sequence polymorphisms contain in intro 6 of the lactate dehydrogenase-A gene to examine the genetic population structure of Pacific swordfish (Xiphias gladius). The examination identified seven alleles defined by five polymorphic sites among 305 swordfish. Comparison of allele frequencies were conducted.

Microsatellite loci are popular molecular markers due to their resolution in distinguishing individual genotypes. However, they have rarely been used to explore the population dynamics in species with biphasic life cycles in which both haploid and diploid stages develop into independent, functional organisms. We developed microsatellite loci for the haploid-diploid red seaweed Gracilaria vermiculophylla, a widespread non-native species in coastal estuaries of the Northern hemisphere. Forty-two loci were screened for amplification and polymorphism. Nine of these loci were polymorphic across four populations of the extant range with two to eleven alleles observed. Mean observed and expected heterozygosities ranged from 0.265 to 0.527 and 0.317 to 0.387, respectively. Overall, these markers will aid in the study of the invasive history of this seaweed and further studies on the population dynamics of this important haploid-diploid primary producer.