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'''Recombinases''' are [[genetic recombination]] enzymes. DNA recombinases are widely used in multicellular organisms to manipulate the structure of [[genome]]s, and to control [[gene expression]]. These enzymes, derived from [[bacteria]] and [[fungi]], catalyze directionally sensitive DNA exchange reactions between short (30–40 [[nucleotide]]s) target site sequences that are specific to each recombinase. These reactions enable four basic functional modules, excision/insertion, inversion, translocation and [[Gene cassette|cassette]] exchange, which have been used individually or combined in a wide range of configurations to control gene expression.<ref>{{cite journal|last1=Nern|first1=A|last2=Pfeiffer|first2=BD|last3=Svoboda|first3=K|last4=Rubin|first4=GM|title=Multiple new site-specific recombinases for use in manipulating animal genomes.|journal=Proceedings of the National Academy of Sciences of the United States of America|date=Aug 23, 2011|volume=108|issue=34|pages=14198–203|pmid=21831835|doi=10.1073/pnas.1111704108}}</ref><ref>{{cite journal|last1=García-Otín|first1=AL|last2=Guillou|first2=F|title=Mammalian genome targeting using site-specific recombinases.|journal=Frontiers in bioscience : a journal and virtual library|date=Jan 1, 2006|volume=11|pages=1108–36|pmid=16146801|doi=10.2741/1867}}</ref><ref>{{cite journal|last1=Dymecki|first1=SM|last2=Kim|first2=JC|title=Molecular neuroanatomy's "Three Gs": a primer.|journal=Neuron|date=Apr 5, 2007|volume=54|issue=1|pages=17–34|pmid=17408575|doi=10.1016/j.neuron.2007.03.009}}</ref><ref>{{cite journal|last1=Luan|first1=H|last2=White|first2=BH|title=Combinatorial methods for refined neuronal gene targeting.|journal=Current opinion in neurobiology|date=Oct 2007|volume=17|issue=5|pages=572–80|pmid=18024005|doi=10.1016/j.conb.2007.10.001}}</ref><ref>{{cite journal|last1=Fenno|first1=LE|last2=Mattis|first2=J|last3=Ramakrishnan|first3=C|last4=Hyun|first4=M|last5=Lee|first5=SY|last6=He|first6=M|last7=Tucciarone|first7=J|last8=Selimbeyoglu|first8=A|last9=Berndt|first9=A|last10=Grosenick|first10=L|last11=Zalocusky|first11=KA|last12=Bernstein|first12=H|last13=Swanson|first13=H|last14=Perry|first14=C|last15=Diester|first15=I|last16=Boyce|first16=FM|last17=Bass|first17=CE|last18=Neve|first18=R|last19=Huang|first19=ZJ|last20=Deisseroth|first20=K|title=Targeting cells with single vectors using multiple-feature Boolean logic.|journal=Nature methods|date=Jul 2014|volume=11|issue=7|pages=763–72|pmid=24908100|doi=10.1038/nmeth.2996}}</ref>
==Geografi og demografi==
Romerriget var en af de største imperier i historien, med en udstrækning som strakte sig over både Europa, Nordafrika og Mellemøsten.<ref name="Kelly, The Roman Empire, p. 3">Kelly, ''The Roman Empire,'' p. 3.</ref> Det latinske udtryk ''imperium sine fine'' ("imperium uden ende"<ref>Nicolet, ''Space, Geography, and Politics in the Early Roman Empire'', p. 29; translated as "power without end" in Pat Southern, ''The Roman Empire from Severus to Constantine'' (Routledge, 2001), p. 16.</ref>) udtrykte ideologien, at hverken tid eller rum begrænsede imperiet. i [[Vergil]] episke digt ''[[Æneiden]]'', skrives det at det grænseløs imperium er givet til romerne af deres øverste guddom [[Jupiter (gud)|Jupiter]].<ref>Vergil, ''Aeneid'' 1.278; Nicolet, ''Space, Geography, and Politics,'' p. 29; David J. Mattingly, ''Imperialism, Power, and Identity: Experiencing the Roman Empire'' (Princeton University Press, 2011), p. 15; G. Moretti, "The Other World and the 'Antipodes': The Myth of Unknown Countries between Antiquity and the Renaissance," in ''The Classical Tradition and the Americas: European Images of the Americas'' (Walter de Gruyter, 1993), p. 257; Southern, ''The Roman Empire from Severus to Constantine,'' p. 16.</ref> Denne påstand om universelle herredømme blev fornyet og foreviget da imperiet kom under kristent styre i det 4. århundrede.<ref>[[Prudentius]] (348–413) in particular Christianizes the theme in his poetry, as noted by Marc Mastrangelo, ''The Roman Self in Late Antiquity: Prudentius and the Poetics of the Soul'' (Johns Hopkins University Press, 2008), pp. 73, 203. [[St. Augustine]], however, distinguished between the secular and eternal "Rome" in ''[[De Civitate Dei|The City of God]].'' See also [[J. Rufus Fears]], "The Cult of Jupiter and Roman Imperial Ideology," ''Aufstieg und Niedergang der römischen Welt'' II.17.1 (1981), p. 136 ''et passim'', on how Classical Roman ideology influenced Christian Imperial doctrine; Peter Fibiger Bang, "The King of Kings: Universal Hegemony, Imperial Power, and a New Comparative History of Rome," in ''The Roman Empire in Context: Historical and Comparative Perspectives'' (John Wiley & Sons, 2011); and the Greek concept of globalism ''([[ecumene|oikouménē]]).''</ref>
Types include:
I virkeligheden var det af romerske ekspansion udført under republikken, med kun få store erobringer under kejserdømme, såsom [[Claudius]] erobring af [[England]] i det 1. århundrede e.Kr og [[Trajan|Trajans]] erobringer af [[Dacia]] og [[Babylon]]. Under regeringstid af Augustus, blev en "global kort over den kendte verden", vist for første gang offentligt i Rom, hvilket faldt sammen med sammensætningen af de mest omfattende værk om den politiske geografi, der overlever fra antikken, geografi Pontic fra græske forfatter [[Strabo]].<ref>Nicolet, ''Space, Geography, and Politics,'' pp. 7–8.</ref> Da Augustus døde, erindringsmønter hensyn til hans resultater (Res Gestae) fremtrædende indholdte geografiske katalogisering af folk og steder i imperiet.<ref>Nicolet, ''Space, Geography, and Politics,'' pp. 9, 16.</ref> Geografi, folketællingen, og den omhyggelige opbevaring af skriftlige optegnelser var centrale bekymringer for den romerske kejserlige administration.<ref>Nicolet, ''Space, Geography, and Politics,'' pp. 10–11.</ref>
* [[Cre recombinase]]
* [[Hin recombinase]]
* [[Tre recombinase]]
* [[FLP recombinase]]
==References==
[[File:Hadrian's Wall and Highshield Crags - geograph.org.uk - 1410581.jpg|thumb|upright=1.2|A segment of the ruins of Hadrian's Wall in northern England]]
{{Reflist|2}}
Imperiet nåede sin største udstrækning under Trajan (regerede 98-117),<ref>Southern, ''The Roman Empire from Severus to Constantine'', p. 14.</ref> hvor det omfattede et areal på 5 millioner kvadratkilometer, som under nutidens grænsen ville strække over fyrre forskellige moderne lande.<ref name="Keith Hopkins 2009 p. 183">Keith Hopkins, "The Political Economy of the Roman Empire," in ''The Dynamics of Ancient Empires : State Power from Assyria to Byzantium'' (Oxford University Press, 2009), p. 183.</ref> Forskellige demografiske befolkning-skøn ligger på imellem 60-100 millioner indbyggere under romerrigets største udbredelse.<ref name="Kelly, The Roman Empire, p. 1">Kelly, ''The Roman Empire,'' p. 1.</ref> Hvilket ville betyde at romerriget inkluderede imellem en sjettedel og en fjerdedel af verdens samlede befolkning<ref name="Hopkins p. 184">Hopkins, "The Political Economy of the Roman Empire," p. 184.</ref> og har være det største befolkningsmæssige rige under én politisk administration i Vesten, indtil midten af det 19. århundrede.<ref>[[Raymond W. Goldsmith]],"An Estimate of the Size and Structure of the National Product of the Early Roman Empire", ''Review of Income and Wealth'', 30.3 (1984), pp. 263–288, especially p. 263.</ref><ref name="Population and demography">Walter Scheidel: ''[http://www.princeton.edu/~pswpc/pdfs/scheidel/040604.pdf Population and demography]'', Princeton/Stanford Working Papers in Classics, Version 1.0, April 2006, p. 9</ref> Hver af de tre største Byer i Imperiet; [[Rom]], [[Alexandria]], og [[Antioch]] var næsten dobbelt så store som enhver Europæisk by i begyndelsen af det 17. århundrede.<ref>W.V. Harris, "Trade," in ''The Cambridge Ancient History: The High Empire A.D. 70–192'' (Cambridge University Press, 2000), vol. 11, p. 721.</ref>
== External links ==
Trajans efterfølger [[Hadrian]] førte en politik om at opretholde imperiet istedet for at udvide det. Grænser blev markeret og patruljeret.<ref>Southern, ''The Roman Empire from Severus to Constantine,'' pp. 14–16.</ref> De mest stærkt befæstede grænser var de mest ustabile.<ref>Olivier Hekster and Ted Kaizer, preface to ''Frontiers in the Roman World. Proceedings of the Ninth Workshop of the International Network Impact of Empire (Durhan, 16–19 April 2009)'' (Brill, 2011), p. viii.</ref> [[Hadrians mur]] i nutidens [[Skotland]] og England er en af de mest velbevarende romerske ydergrænser, blev af romerne selv opfattet, som hvad der adskilte romerriget fra den altid tilstedeværende trussel fra barbarer.<ref>Greg Woolf, editor, ''Cambridge Illustrated History of the Roman World'' (Cambridge: Ivy Press, 2003), p. 340; Thorsten Opper, ''Hadrian: Empire and Conflict'' (Harvard University Press, 2008), p. 64; Nic Fields, ''Hadrian's Wall AD 122–410, which was, of course, at the bottom of Hadrian's garden.'' (Osprey Publishing, 2003), p. 35.</ref> <!--a couple of sentences on the loss of territories goes here, with the final east–west split-->
*{{MeshName|Recombinases}}
[[Category:Molecular biology]]
{{Genetics-stub}}
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