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We have employed herbarium specimens, historical records and molecular techniques in reconstructing the introduction and spread of Bromus tectorum L. (or Anisantha tectorum [L.] Nevski [Stace 1997]) (Figure 1) into North America and other portions of the grass's naturalized ranges (Novak et al. 1991, Novak and Mack 1993, Novak et al. 1993). We summarize in this article a portion of our findings from this ongoing effort. Published in Bioscience, volume 51, issue 2, on pages 114 - 122, in 2001.
Categories: Publication; Types: Citation, Journal Citation; Tags: Bioscience
The amount and distribution of genetic variation in 51 native (Eurasian and northern African) populations of Bromus tectorum were assessed at 25 loci using starch gel electrophoresis and were compared with our previous results for introduced (North American) populations of this predominantly cleistogamous grass. More alleles and variable loci were detected across populations in the native range than in North American populations. Within populations, however, the level of polymorphism is higher in the introduced range than in the native range. Deviation from Hardy-Weinberg expectation among native populations is almost as severe as for introduced populations. Eurasian populations exhibit greater genetic differentiation...
Biological invasions can be substantially influenced by the genetic sampling associated with a species? introduction. As a result, we assessed the genetic and evolutionary consequences of the entry and spread of the invasive grass Bromus tectorum (cheatgrass) across the United States midcontinent through an analysis of 54 populations, using enzyme electrophoresis. On average, these populations display 1.04 alleles per locus (A), 4.1% percent polymorphic loci per population (%P) and an expected mean heterozygosity (Hexp) value of 0.009. Heterozygotes, which have been rarely reported for B. tectorum in North America, occur in three populations in the midcontinent and are likely novel multilocus genotypes that arose...