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ELEANOR P. JONES JENS‐KJELD JENSEN EYĐFINN MAGNUSSEN NOOMI GREGERSEN HEIDI S. HANSEN JEREMY B. SEARLE 《Biological journal of the Linnean Society. Linnean Society of London》2011,102(3):471-482
Faroe house mice are a ‘classic’ system of rapid and dramatic morphological divergence highlighted by J. S. Huxley during the development of the Modern Synthesis. In the present study, we characterize these charismatic mice using modern molecular techniques, examining specimens from all Faroe islands occupied by mice. The aims were to classify the mice within the modern house mouse taxonomy (i.e. as either Mus musculus domesticus or Mus musculus musculus) using four molecular markers and a morphological feature, and to examine the genetic diversity and possible routes of colonization using mitochondrial (mt) control region DNA sequences and microsatellite data (15 loci). Mice on the most remote islands were characterized as M. m. domesticus and exhibited exceptionally low genetic diversity, whereas those on better connected islands were more genetically diverse and had both M. m. musculus and M. m. domesticus genetic elements, including one population which was morphologically M. m. musculus‐like. The mtDNA data indicate that the majority of the mice had their origins in south‐western Norway (or possibly southern Denmark/northern Germany), and probably arrived with the Vikings, earlier than suggested by Huxley. The M. m. musculus genetic component appears to derive from recent mouse immigration from Denmark. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 471–482. 相似文献
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Abstract. An increase in egg size with embryonic development in stoneflies is believed to result from the uptake of water by osmosis. The present study aims to investigate whether a selective ion transport through egg membranes exists before hatching, and whether ions are released after hatching. Viable and nonviable egg masses are incubated in Petri dishes filled with water, and the concentrations of the ions F− , Cl− , SO4 2− , NO3 − , Na+ , K− , Mg2+ and Ca2+ in the water are determined. The ion transport of an egg mass before and after hatching and a nonviable egg mass is then calculated. Before hatching, Cl− , SO4 2− , NO3 − , Na+ , Mg2+ and Ca2+ are taken up from the surrounding water into the inner egg. These ions are selectively taken into the egg. After hatching, Cl− , SO4 2− , Na+ , Mg2+ and Ca2+ are released into the surrounding water. The amount of these ions released after hatching is lower than the amount taken up before hatching. Ions that are not released after hatching are considered to be used in embryonic development. 相似文献
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Developmental morphology of the ovules of Amborella trichopoda (Amborellaceae) and Chloranthus serratus (Chloranthaceae) 总被引:2,自引:0,他引:2
TOSHIHIRO YAMADA HIROSHI TOBE RYOKO IMAICHI MASAHIRO KATO 《Botanical journal of the Linnean Society. Linnean Society of London》2001,137(3):277-290
The developmental morphology of the outer integument in the pendent orthotropous ovules of Amborella trichopoda (Amborellaceae) and Chloranthus serratus (Chloranthaceae) was studied. In both species the outer integument is semiannular at an early stage and becomes cup-shaped but dorsiventrally somewhat asymmetric at later stages. The outer integument, which is initiated first on the concave and lateral sides of the ovule, differs from that of the anatropous ovules of other basal families with the outer integument semiannular at an early stage or throughout development. The bilateral symmetry of the outer integument is shared by these orthotropous and anatropous ovules. The developmental pattern of the outer integument and ovule incurving characterize the ovule of the Amborellaceae and Chloranthaceae, which is not equivalent to typical orthotropous ovules of eudicots. A phylogenetic analysis of ovule characters in basal angiosperms suggests that anatropous ovules with cup-shaped outer integuments and orthotropous ovules were derived independently in several clades and that the ovules of Amborella and Chloranthus might also be derivative. 相似文献
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YO TOMA FABIÁN G. FERNÁNDEZ SYOHEI SATO MIKI IZUMI RYUSUKE HATANO TOSHIHIKO YAMADA AYA NISHIWAKI GERMÁN BOLLERO J. RYAN STEWART 《Global Change Biology Bioenergy》2011,3(2):116-134
Species in the Miscanthus genus have been proposed as biofuel crops that have potential to mitigate elevated atmospheric carbon dioxide (CO2) levels and nitrous oxide (N2O) and methane (CH4) emissions. Miscanthus sinensis is widespread throughout Japan and has been used for biomass production for centuries. We assessed the carbon (C) budget and N2O and CH4 emissions over the growing season for 2 years in a M. sinensis‐dominated grassland that was naturally established around 1972 in Tomakomai, Hokkaido, Japan, which is near the northern limit for M. sinensis grassland establishment on Andisols. Average C budget was ?0.31 Mg C ha?1, which indicates C was released from the grassland ecosystem to the atmosphere. Dominant components in the C budget appeared to be aboveground net primary production of plants (1.94–2.80 Mg C ha?1) and heterotrophic respiration (2.27–3.11 Mg C ha?1). The measurement of belowground net primary production (BNPP) of plants in the M. sinensis grassland was extremely variable, thus only an approximate value could be calculated. Mean C budget calculated with the approximated BNPP value was 1.47 and ?0.23 Mg C ha?1 for 2008 and 2009, respectively. Given belowground biomass (9.46–9.86 Mg C ha?1) was 3.1–6.5 times higher than that of aboveground biomass may provide additional evidence suggesting this grassland represents a C sink. Average CH4 emissions across years of ?1.34 kg C ha?1 would indicate this grassland acts as an atmospheric CH4 sink. Furthermore, average N2O emissions across years were 0.22 kg N ha?1. While the site may contribute N2O to the atmosphere, this value is lower compared with other grassland types. Global warming potential calculated with the approximated BNPP value was ?5.40 and 0.95 Mg CO2 Eq ha?1 for 2008 and 2009, respectively, and indicates this grassland could contribute to mitigation of global warming. 相似文献
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SHINNOSUKE YAMADA AKIRA TSUKAGOSHI NORIYUKI IKEYA 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2005,38(4):323-332
Details of ostracode carapace structures were examined by SEM and TEM. The podocopine ostracode Semicytherura kazahana has major ridges on the carapace surface and develops its prismatic layer inside the adult carapace. Electron microscopy at the final molt reveals that the major ridges arise from the highly dense formation of pits within the underlying swollen epidermis, and that disappearance of the epidermis in the presumptive area of the prismatic layer occurs after the calcification of the outer lamella cuticle, and just before synthesis of the membranous layer. These facts suggest that the formation of the carapace in Semicytherura takes place via a more complex process than that of the other podocopid ostracodes. 相似文献
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