Mark E. Mort

Bio: Mark E. Mort is an academic researcher from Washington State University. The author has contributed to research in topics: Monophyly & Malpighiales. The author has an hindex of 4, co-authored 5 publications receiving 1433 citations. Previous affiliations of Mark E. Mort include Eastern Illinois University.

Phylogenetic relationships and evolution of Crassulaceae inferred from matK sequence data

Abstract: Chloroplast gene matK sequence data were used to estimate the phylogeny of 112 species of Crassulaceae sampled from 33 genera and all six recognized subfamilies. Our analyses suggest that five of six subfamilies recognized in the most recent comprehensive classification of the family are not monophyletic. Instead, we recovered a basal split in Crassulaceae between the southern African CRASSULA: clade (Crassuloideae) and the rest of the family (Sedoideae). These results are compatible with recent studies of cpDNA restriction site analyses. Within Sedoideae, four subclades were also recovered: KALANCHOE:, Leucosedum, Acre, and AEONIUM:; evidence also exists for a TELEPHIUM: clade and SEMPERVIVUM: clade. The genus SEDUM: is highly polyphyletic with representatives spread throughout the large Sedoideae clade. Sympetaly and polymerous flowers have arisen multiple times in Crassulaceae and thus are not appropriate characters upon which to base subfamilial limits, as has been done in the past. One floral character, haplostemy, appears to be confined to the well-supported CRASSULA: clade. Our analyses suggest a southern African origin of the family, with subsequent dispersal northward into the Mediterranean region. From there, the family spread to Asia/eastern Europe and northern Europe; two separate lineages of European Crassulaceae subsequently dispersed to North America and underwent substantial diversification. Our analyses also suggest that the original base chromosome number in Crassulaceae is x = 8 and that polyploidy has played an important role in seven clades. Three of these clades are exclusively polyploid (SEMPERVIVUM: clade and two subclades within the KALANCHOE: and AEONIUM: clades), whereas four (Crassula, Telephium, Leucosedum, and ACRE: clades) comprise both diploid and polyploid taxa. Polyploidy is particularly rampant and cytological evolution especially complex in the ACRE: clade.

Tolpis (asteraceae-lactuceae) in the canary islands: systematic, evolutionary, and biogeographical implications 1

Abstract: Plants endemic to oceanic islands represent some of the most unusual and rare taxa in the world. Enzyme electrophoresis was used to assess genetic diversity within and divergence among all endemic species of a small genus of plants on the Canary Islands. Our results show that the genus Tolpis is similar to many other island groups in having generally low allozyme divergence among species, with the highest divergence found among four groups of endemics. The two rare and highly localized species T. glabrescens and T. crassiuscula are each divergent from all other species in the Canaries. Tolpis coronopifolia is also divergent at allozyme loci; this is the only endemic species that is a self-compatible annual (or weak biennial). A large, morphologically variable species complex consisting of T. laciniata and T. lagopoda together with several named and unnamed morphological variants shows low allozyme divergence among its elements. The evolution of polyploidy from diploid ancestors in situ in oceanic archipelagos is uncommon, but the tetraploid T. glabrescens is an exception. Allozyme data do not implicate any extant diploid Tolpis species as parents of the polyploid. It is possible that T. glabrescens originated early in the evolution of Tolpis in the Canary Islands and that its parents are now extinct. The nonendemic T. barbata shows no greater divergence from the Canary Island endemics than some endemics exhibit among themselves. Both changes in allele frequencies and unique alleles are responsible for genetic divergence among species of Tolpis.

The Families And Genera Of Vascular Plants

Abstract: Perp. punya vol. X. Flowering plant, eudicots : sapindales, cucurbitales, myrtaceae. Perp.punya: 1eks.

Bayesian inference of phylogeny and its impact on evolutionary biology

Abstract: As a discipline, phylogenetics is becoming transformed by a flood of molecular data. These data allow broad questions to be asked about the history of life, but also present difficult statistical and computational problems. Bayesian inference of phylogeny brings a new perspective to a number of outstanding issues in evolutionary biology, including the analysis of large phylogenetic trees and complex evolutionary models and the detection of the footprint of natural selection in DNA sequences.

Phylogenetic distribution and evolution of mycorrhizas in land plants

Abstract: A survey of 659 papers mostly published since 1987 was conducted to compile a checklist of mycorrhizal occurrence among 3,617 species (263 families) of land plants. A plant phylogeny was then used to map the mycorrhizal information to examine evolutionary patterns. Several findings from this survey enhance our understanding of the roles of mycorrhizas in the origin and subsequent diversification of land plants. First, 80 and 92% of surveyed land plant species and families are mycorrhizal. Second, arbuscular mycorrhiza (AM) is the predominant and ancestral type of mycorrhiza in land plants. Its occurrence in a vast majority of land plants and early-diverging lineages of liverworts suggests that the origin of AM probably coincided with the origin of land plants. Third, ectomycorrhiza (ECM) and its derived types independently evolved from AM many times through parallel evolution. Coevolution between plant and fungal partners in ECM and its derived types has probably contributed to diversification of both plant hosts and fungal symbionts. Fourth, mycoheterotrophy and loss of the mycorrhizal condition also evolved many times independently in land plants through parallel evolution.

Evolution of the angiosperms: calibrating the family tree.

Abstract: Growing evidence of morphological diversity in angiosperm flowers, seeds and pollen from the mid Cretaceous and the presence of derived lineages from increasingly older geological deposits both imply that the timing of early angiosperm cladogenesis is older than fossil-based estimates have indicated. An alternative to fossils for calibrating the phylogeny comes from divergence in DNA sequence data. Here, angiosperm divergence times are estimated using non-parametric rate smoothing and a three-gene dataset covering ca. 75% of all angiosperm families recognized in recent classifications. The results provide an initial hypothesis of angiosperm diversification times. Using an internal calibration point, an independent evaluation of angiosperm and eudicot origins is performed. The origin of the crown group of extant angiosperms is indicated to be Early to Middle Jurassic (179-158 Myr), and the origin of eudicots is resolved as Late Jurassic to mid Cretaceous (147-131 Myr). Both estimates, despite a conservative calibration point, are older than current fossil-based estimates.