Geographical parthenogenesis in Pacific Northwest hawthorns (Crataegus; Rosaceae)

E.Y.Y. Lo; S. Stefanović; T.A. Dickinson

doi:10.1139/cjb-2012-0073

Geographical parthenogenesis in Pacific Northwest hawthorns (Crataegus; Rosaceae)

Botany ◽

10.1139/cjb-2012-0073 ◽

2013 ◽

Vol 91 (2) ◽

pp. 107-116 ◽

Cited By ~ 13

Author(s):

E.Y.Y. Lo ◽

S. Stefanović ◽

T.A. Dickinson

Keyword(s):

Pacific Northwest ◽

Nuclear Dna ◽

Extreme Temperature ◽

Nuclear Dna Content ◽

Molecular Data ◽

Great Lakes Basin ◽

Upper Great Lakes ◽

The Pacific ◽

Evolutionary Context ◽

Geographical Parthenogenesis

We have demonstrated geographical parthenogenesis in Crataegus series Douglasianae, an agamic complex comprising exclusively tetraploid Crataegus douglasii sensu lato and the morphologically distinct Crataegus suksdorfii complex that comprises diploids and polyploids. Here we characterize ploidy level and breeding system by detailed flow cytometric measurements of the 2C nuclear DNA content of leaf, embryo, and endosperm tissues from 282 black-fruited hawthorns (Crataegus series Douglasianae) representing 33 localities in the Pacific Northwest, one in the Cypress Hills, and three more in the upper Great Lakes basin. We use existing climate and molecular data to place our flow cytometry results in an environmental and evolutionary context. Crataegus douglasii occupies more widely distributed sites that experience more extreme temperature and moisture regimes than do the sites occupied by diploid C. suksdorfii.

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Analysis of a polyploid complex in Glycine with chloroplast and nuclear DNA

Australian Systematic Botany ◽

10.1071/sb9900125 ◽

1990 ◽

Vol 3 (1) ◽

pp. 125 ◽

Cited By ~ 26

Author(s):

JJ Doyle ◽

JL Doyle ◽

AHD Brown

Keyword(s):

Nuclear Dna ◽

Molecular Data ◽

Polyploid Complex ◽

Diploid Progenitor ◽

Nuclear Rdna ◽

Central Pacific ◽

Geographic Ranges ◽

The Pacific ◽

Repeat Class ◽

Molecular Characters

Studies of chloroplast DNA and nuclear 18s–25s ribosomal genes have revealed considerable variation in Glycine subgenus Glycine, the perennial relatives of the cultivated annual soybean. We have used these molecular characters to investigate the origins and evolution of G. tabacina, a species that comprises a widespread polyploid complex in Australia and the islands of the southern and west-central Pacific. Two principal groups of accessions were detected in this species using molecular characters. These two types also differ morphologically and have distinct, though overlapping, geographic ranges; comparison with results of artificial hybridisation studies showed that sterility barriers exist between the two groups. Both types are fixed hybrids for nuclear rDNA, and share one rDNA repeat class, presumably derived from a common diploid progenitor. The two types had different maternal progenitors, based on cpDNA variation. One of the two polyploid types is polymorphic for cpDNA, and shares nearly all of its plastome variants with diploid accessions, suggesting multiple, independent origins of the polyploid from a pool of diploid progenitors. Molecular data suggest that polyploids have originated recently, and that dispersal from Australia to the islands of the Pacific has occurred several times.

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Determining Ploidy Level and Nuclear DNA Content in Rubus by Flow Cytometry

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.127.5.767 ◽

2002 ◽

Vol 127 (5) ◽

pp. 767-775 ◽

Cited By ~ 37

Author(s):

Rengong Meng ◽

Chad Finn

Keyword(s):

Flow Cytometry ◽

Pacific Northwest ◽

Ploidy Level ◽

Dna Content ◽

Chromosome Numbers ◽

Nuclear Dna ◽

Diploid Species ◽

Nuclear Dna Content ◽

Dna Flow Cytometry ◽

Ploidy Levels

Nuclear DNA flow cytometry was used to differentiate ploidy level and determine nuclear DNA content in Rubus. Nuclei suspensions were prepared from leaf discs of young leaves following published protocols with modifications. DNA was stained with propidium iodide. Measurement of fluorescence of 40 genotypes, whose published ploidy ranged from diploid to dodecaploid, indicated that fluorescence increased with an increase in chromosome number. Ploidy level accounted for 99% of the variation in fluorescence intensity (r2 = 0.99) and variation among ploidy levels was much higher than within ploidy levels. This protocol was used successfully for genotypes representing eight different Rubus subgenera. Rubus ursinus Cham. and Schldl., a native blackberry species in the Pacific Northwest, which has been reported to have 6x, 8x, 9x, 10x, 11x, and 12x forms, was extensively tested. Genotypes of R. ursinus were predominantly 12x, but 6x, 7x, 8x, 9x, 11x, and 13x forms were found as well. Attempts to confirm the 13x estimates with manual counts were unsuccessful. Ploidy level of 103 genotypes in the USDA-ARS breeding program was determined by flow cytometry. Flow cytometry confirmed that genotypes from crosses among 7x and 4x parents had chromosome numbers that must be the result of nonreduced gametes. This technique was effective in differentiating chromosome numbers differing by 1x, but was not able to differentiate aneuploids. Nuclear DNA contents of 21 diploid Rubus species from five subgenera were determined by flow cytometry. Idaeobatus, Chamaebatus, and Anaplobatus were significantly lower in DNA content than those of Rubus and Cylactis. In the Rubus subgenus, R. hispidus and R. canadensis had the lowest DNA content and R. sanctus had the highest DNA content, 0.59 and 0.75 pg, respectively. Idaeobatus had greater variation in DNA content among diploid species than the Rubus subgenus, with the highest being from R. ellipticus (0.69 pg) and lowest from R. illecebrosus (0.47 pg).

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