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31.
Chris Christiansen Thomas Mailund Christian NS Pedersen Martin Randers Martin Stig Stissing 《Algorithms for molecular biology : AMB》2006,1(1):16-13
Background
A number of algorithms have been developed for calculating the quartet distance between two evolutionary trees on the same set of species. The quartet distance is the number of quartets – sub-trees induced by four leaves – that differs between the trees. Mostly, these algorithms are restricted to work on binary trees, but recently we have developed algorithms that work on trees of arbitrary degree. 相似文献32.
Jo?o V Neves Jonathan M Wilson Heiner Kuhl Richard Reinhardt L Filipe C Castro Pedro NS Rodrigues 《BMC evolutionary biology》2011,11(1):106
Background
The SLC11A1/Nramp1 and SLC11A2/Nramp2 genes belong to the SLC11/Nramp family of transmembrane divalent metal transporters, with SLC11A1 being associated with resistance to pathogens and SLC11A2 involved in intestinal iron uptake and transferrin-bound iron transport. Both members of the SLC11 gene family have been clearly identified in tetrapods; however SLC11A1 has never been documented in teleost fish and is believed to have been lost in this lineage during early vertebrate evolution. In the present work we characterized the SLC11 genes in teleosts and evaluated if the roles attributed to mammalian SLC11 genes are assured by other fish specific SLC11 gene members. 相似文献33.
DAVID B. IRONS TYCHO ANKER-NILSSEN† ANTHONY J. GASTON‡ G. VERNON BYRD§ KNUD FALK¶ GRANT GILCHRIST‡ MARTTI HARIO MÅNS HJERNQUIST YURI V. KRASNOV†† ERS MOSBECH‡‡ BERGUR OLSEN§§ AEVAR PETERSEN¶¶ JAMES B. REID GREGORY J. ROBERTSON HALLVARD STRØM††† KENTON D. WOHL 《Global Change Biology》2008,14(7):1455-1463
We found that synchronous fluctuations of two congeneric seabird species across the entire Arctic and sub-Arctic regions were associated with changes in sea surface temperatures (SST) that were linked to two climate shifts, in 1977 and again in 1989. As the SST changes linked to climate shifts were congruent at the scale of ocean basins, fluctuations of these species occurred similarly at continental or basin scale. Changes in colony sizes were examined for a decade following climate shifts. The magnitude of the SST shift was more important than its direction in determining the subsequent rate of population change. Seabirds declined when the SST shift was large and increased when the shift was small, although the effect differed between the Arctic-breeding species and the more temperate-breeding congener. The Arctic species, Thick-billed Murre ( Uria lomvia ) increased most rapidly when SST warmed slightly, while the temperate species, Common Murre ( Uria aalge ) showed most rapid increase with moderate cooling. Both showed negative trends with large temperature shifts in either direction. This pattern was replicated during both climate oscillations. Negative population trends in seabirds presumably indicate the alteration of underlying food webs. Hence, similar widespread fluctuations in response to climate shifts are likely for other ecosystem components (marine mammals, fish, and invertebrates). 相似文献
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