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投稿者：shinok30
投稿日：2009年 6月 6日(土)00時01分11秒
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＞陸イグアナと海イグアナの遺伝子の異いいもしくは
＞染色体の数についての文献または情報はあるのでしょうか。あればご紹介ください。
ガラパゴス諸島には３種のリクイグアナ（ガラパゴスリクイグアナ，サンタフェリクイグアナ，
ピンクリクイグアナ）と１種のウミイグアナがいます
（このうちピンクリクイグアナは最近確認されたもののようです）
＞ウミイグアナ Ｍarine iguana
＞ウミイグアナ（学名 Amblyrhynchus cristatus）は、ガラパゴスの固有種でいろいろな
＞島の海岸で見ることができる。
＞
＞リクイグアナ Galapagos land iguana
＞ウミイグアナとは別に、陸生で海に潜ることはないリクイグアナもいる。黒っぽい
＞ウミイグアナと違い、頭の部分が黄色なのですぐに見分けることができる。
＞
＞リクイグアナは２種に分類されている。いくつかの島に分布しているのは Conolophus
＞subcristatusで、別の１種 C. pallidusはサンタフェ島のみでみられる。
http://www.hamajima.co.jp/galapagos/galaanim.htm
>2009年1月6日 チャールズ・ダーウィン財団
>●ウォルフ火山のピンクイグアナは新種であると同定
>発表された論文
>PNAS:An overlooked pink species of land iguana in the Galápagos
>http://www.pnas.org/content/early/2009/01/05/0806339106
http://galanews.ti-da.net/e2392401.html
＞Vol. 442(2009/1/25) [今日の事件]新種はピンクのリクイグアナ
http://ikimonotuusin.com/doc/442.htm
ガラパゴスリクイグアナやガラパゴスのヨウガントカゲ（Tropidurus albemarlensis, T. delanonis, and T. dnncanensis）の染色体数は
2n=36(12本の大染色体と24本の小染色体からなる）という報告があります
イグアナ科の他のグループの染色体数も参照すると，
ウミイグアナも2n=36か34の可能性が高いと思いますよ
>LIZARD KARYOTYPES FROM THE GALAPAGOS ISLANDS: CHROMOSOMES IN PHYLOGENY AND EVOLUTION
>D. PAULL,1 E. E. WiLLIAMS1 AND W. P. HALL2
>
>ABSTRACT
>
>The iguanid lizards, Conolophus subscristatus, Tropidurus albemarlensis, T. delanonis, and
> T. dnncanensis have similar 2n = 36 karyotypes. C. subcristatus has a 12 metacentric
> macrochromosome and 24 microchromosome karyotype that is here shown to be primitive for
> the Ignanidae and probably for all lizards, while the three Galapagos Tropidurus have
> identical patterns to Tropidurus species from eastern South America and differ from the
> primitive karyotype of C. subcristatus by non-Robertsonian modifications of three pairs
> of macrochromosomes.
>
>All available karyotypic data for the Iguanidae are summarized and used to discuss how one
> may determine which karyotypes are "primitive" within radiations and what possible roles
> Robertsonian karyotypic variation may play in the process of evolution. Analysis of
> karyotypic and systematic information suggests a causal relationship between karyotypic
> differentiation and the rapid proliferation of new species, such that the need for
> geographic isolation seems to be minimized bv the chromosomal differentiation.
>
>
>KARYOTYPES OF GALAPAGOS IGUANIDS
>
>(D. PAULL AND W. P. HALL)
>
>Specimens examined:
>
>Representatives of two distantly related branches of the Iguanidae have reached the
> Galapagos, presumably by overwater colonization. The iguanine species in the Galapagos
> belong to the endemic genera Amblyrhynchus (one species, the marine iguana) and Conolophus
> (two species of land iguanas). Of these, Conolophus subcristatus was karyotvped. The
> tropidurine radiation is represented in the archipelago by eight endemic species of
> Tropidurus (lava lizards). Additionally, Tropidurus has a South American continental
> radiation of 12 species (Etheridge in Peters and Donoso-Barros 1970). Island species
> karyotyped were Tropidurus albemarlensis, T. delanonis and T. duncanensis. Table 1 lists
> the species karyotyped and their collection localities. Methods: All chromosome
> preparations were made in the Galapagos Islands using laboratory facilities kindly
> supplied by the Charles Darwin Research Station on Santa Cruz Island. Cells were spread
> for karyotyping by air drying smears of methanol: acetic acid (3:1) fixed suspensions of
> testis, bone marrow or spleen tissues prepared directly from colchicine pretreated animals.
> The techniques used were similar to those of Evans et al (1964), Bianchi and Contreras
> (1967) and Patton and Hsu (1969).
>
> Results:
>
>All species had 36 chromosomes, with 12 biarmed macrochromosomes and 24 microchromosomes
> (Fig. 1). No cytologically distinct sex chromosomes or intrageneric variation of any kind
> was seen. However, conspicuous differences in arm ratios and relative sizes of the
> macrochromosomes were noted between the genera (Fig. 1).
>
>
> Intergeneric diversity in karyotypes
>
>The deviations from the 12+24 pattern among the small genera are again: Plica (16+24 in no
> more than four mutational events, and possibly in only one, fide Todd, 1970), Iguana
> (12+22 in one event), all of the "primitive" sceloporines (12 + 22 in one event in the
> common ancestry for all species), and Polychrus (2n's= 20-30 resulting from an undetermined
> number of events producing karyotypes derived in relation both to one another and the 12+24
> pattern). Contrasted to the limited intergeneric variation in the family as awhole is the
> remarkable interspecific diversity involving many mutational events found within each of
> the three especially speciose genera (cf. Fig. 3). Again, this relationship is clearest in
> the well-investigated sceloporine lineage (Hall, 1973, in prep.).
http://www.orgs-evolution-knowledge.net/Index/EvolBiolPapers/Content/PaullEtAl1976/lizard_karyotypes_from_the_galap.htm
>Figure 1. Comparison of male karyotypes from Tropidurus delanonis (above) and
> Conolophus subcristatus (below). Both figures are printed to the same magnification
http://www.orgs-evolution-knowledge.net/Index/EvolBiolPapers/Content/PaullEtAl1976/figure_1.htm
>Table 2 Karyotypes in the Family Iguanidae
>
>Genus Number of species in genus Number of species karyotyped Range of known 2n
>
>Conolophus 2 1 2n = 36
http://www.orgs-evolution-knowledge.net/Index/EvolBiolPapers/Content/PaullEtAl1976/table_2.htm
>Figure 3. Phylogeny and karyotype distribution in the family Iguanidae.
http://www.orgs-evolution-knowledge.net/Index/EvolBiolPapers/Content/PaullEtAl1976/figure_3.htm
また，リクイグアナとウミイグアナのミトコンドリアDNAやMHC（主要組織適合遺伝子複合体）配列の比較や
リクイグアナやウミイグアナの個体群間で塩基配列を比較した論文もいくつかありますね
>Rassmann, K., 1997.
>Evolutionary age of the Galápagos iguanas predates the age of the present Galápagos Islands.
>Mol. Phylogenet. Evol. 7, 158–172.8, 1–7.
>Glaberman S, Caccone A., 2008
>Species-specific evolution of class I MHC genes in iguanas (order: Squamata; subfamily: Iguaninae).
>Mol Ecol. 2008 Dec;17(23):4943-52.
>Tzika AC, Rosa SF, Fabiani A, Snell HL, Snell HM, Marquez C, Tapia W, Rassmann K, Gentile G, Milinkovitch MC., 2008
>Population genetics of Galapagos land iguana (genus Conolophus) remnant populations.
>Immunogenetics.60(7):371-82.
>A population genetic analysis of the Galápagos land iguanas
http://www.lanevol.org/LANE/galaplandiguan.html
>Kornelia Rassmann, Diethard Tautz, Fritz Trillmich & Chris Gliddon (1997).
>The microevolution of the Galápagos marine iguanas (Amblyrhynchus cristatus) assessed by nuclear and mitochondrial genetic analyses.
>Molecular Ecology 6, 437-452.
また，ウミイグアナとガラパゴスリクイグアナの間での交雑も確認されていますね
>Kornelia Rassmann, Fritz Trillmich & Diethard Tautz (1997).
>Hybridization between the Galápagos land and marine iguana (Conolophus subcristatus and Amblyrhynchus cristatus) on Plaza Sur.
>Journal of Zoology 242, 729-739.
＞和名：ハイブリッドイグアナ 英名：Hybrid Iguana 学名：Amblyrhynchus cristatus（♂）×Conolophus subcristatus（♀）
＞サウスプラサ島にて撮影。リクイグアナとウミイグアナが交配したとされ、両種のDNAを併せ持ったイグアナ。
＞ウミイグアナの特徴である長い爪が備わっており、その爪を利用し、リクイグアナでは
＞不可能な高木サボテンに登ることが
＞出来るハイブリッド種も生まれている。生殖機能が備わっているかは不明。
http://rikanet2.jst.go.jp/contents/cp0220f/contents/09/090601.html
＞「ウミイグアナ」 と 「リクイグアナ」 の交雑種 （ハイブリッド種）
http://www.youtube.com/watch?v=dbUPX2ULxAc
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