WOS: 000266282200003Constitutive heterochromatin were studied in two Cyprinids Acanthobrama marmid and Cyprinion macrostomus in Turkey. The C-band patterns of the metaphase chromosomes of these species were reported. Diploid chromosome number was 2n=50 in all specimens. The C-bands were seen in the pericentromeric regions of all chromosomes in both species. In addition C-bands were observed on the short arms of two pairs of submetacentric chromosomes of A. marmid and on the short arms of two pairs of submeta-subtelocentric chromosomes of C. macrostomus. There were similarities between C-band blocks and NOR regions. C-band patterns were also similar in both species

Gaffaroglu, Muhammet

Yuksel, Esref

Kafkas Universitesi Veteriner Fakultesi Dergisi

Kırşehir Ahi Evran University Institutional Repository

English

Constitutive heterochromatin in Acanthobrama marmid and Cyprinion macrostomus (Osteichthyes, Cyprinidae)

Acanthobrama marmid (Heckel, 1843) andCyprinion macrostomus (Heckel, 1843) weredistributed eastern Anatolia, Middle East andArabian Peninsula. One hundred sixteen speciesand subspecies of Cyprinidae have been reportedfrom Turkey by Kuru 1. However, cytogenetic studies,concerning fish in this country are not sufficient.There are a few karyological studies and yet studiesabout 2-6, C-banding is really limited 7. Karyotypesand nucleolus organizer region (NOR) characteristicsof C. macrostomus and A. marmid were studied bydifferent researchers 4,6,7. C-banding, used toestablish heterochromatin regions on the chromosomesis frequently used in plants and animals speciallyin mammals and fish and thus is useful for examiningintra and interspesific chromosomal differencesbetween closely related species 8-10. C-bandpatterns are all of similar in pericentromeric hetero-chromatin among plants and animals. However,there is great variation in the distribution ofheterochromatin on chromosomal arms. C-bandsare found at or around pericentric region andKafkas Univ Vet Fak Derg15 (2): 169-172, 2009RESEARCH ARTICLEConstitutive heterochromatin in Acanthobrama marmidand Cyprinion macrostomus (Osteichthyes, Cyprinidae)Muhammet GAFFAROĞLU * Eşref YÜKSEL ** YayHn Kodu (Article Code): 2008/72-ADepartment of Biology, Faculty of Science and Arts, University of Ahi Evran, Kirsehir - TURKEYDepartment of Biology, Faculty of Science and Arts, University of Gazi, Ankara - TURKEY İletişim (Correspondence)℡ +90 386 2114544 mgaffaroglu@yahoo.comSummaryConstitutive heterochromatin were studied in two Cyprinids Acanthobrama marmid and Cyprinionmacrostomus in Turkey. The C-band patterns of the metaphase chromosomes of these species were reported.Diploid chromosome number was 2n=50 in all specimens. The C-bands were seen in the pericentromeric regionsof all chromosomes in both species. In addition C-bands were observed on the short arms of two pairs ofsubmetacentric chromosomes of A. marmid and on the short arms of two pairs of submeta-subtelocentricchromosomes of C. macrostomus. There were similarities between C-band blocks and NOR regions. C-bandpatterns were also similar in both species.Keywords: C-banding, constitutive heterochromatin, Acanthobrama marmid, Cyprinion macrostomus, CyprinidaeAcanthobrama marmid ve Cyprinion macrostomus (Osteichthyes,Cyprinidae)’un Konstitütif HeterokromatiniÖzetTürkiye’de yaşayan iki Cyprinid Acanthobrama marmid ve Cyprinion macrostomus üzerinde konstitütifheterokromatini araştTrTldT. Bu türlerin metafaz kromozomlarTndan C-band kalTplarT rapor edildi. Bütün örneklerdediploid kromozom sayTsT 2n=50 bulundu. Her iki türde de bütün kromozomlarTn perisentromerik bölgelerinde C-band görüldü. AyrTca A. marmid’de iki çift submetasentrik kromozomun kTsa kollarTnda ve C. macrostomus’ta ikiçift submeta-subtelosentrik kromozomun kTsa kollarTnda C-band gözlendi. C-band bloklarT ve NOR bölgeleriarasTnda benzerlikler bulundu. Her iki türün C-band kalTplarT arasTnda da benzerlikler mevcuttu.Anahtar sözcükler: C-bandlama, konstitütif heterokromatin, Acanthobrama marmid,Cyprinion macrostomus, CyprinidaeINTRODUCTION***frequently of the telomeric region and frequentlyat the telomeres. C-bands may also be foundwithin chromosomal arms and occasionally theshort arms of acrocentric chromosomes may beentirely heterochromatin. Investigations aboutheterochromatin differentiation and C-bandpatterns of fish chromosomes are far behind thestudies of all other vertebrates due to the commonreason that relates to the general difficulty isworking with fish chromosomes. There may bedifferences in heterochromatin regions withinchromosomal arms among related genera. Thus inthis paper firstly, we made an attempt to establishthe distribution of heterochromatin and secondly,thus chromosomal evolution and cytotaxonomy oftwo closely related species A. marmid and C.macrostomus.MATERIAL and METHODSAdult males and females of A. marmid (n=8)and C. macrostomus (n=7) were collected fromSultansuyu River in Malatya (38° 26' N, 38° 08' E),Turkey at 2006-2007. Chromosome preparationswere made from head kidney according to themethod of Collares-Pereira with slight modifications 11.The C-bands were stained by the techniques ofSumner 12.  The preparations observed andphotographed digitally at Leica DMLB researchmicroscope. The nomenclature of Levan et al. wasused to describe to chromosome morphology 13.Specimens analyzed were deposited as vouchersin the Cytogenetics Laboratory of Department ofBiology, Faculty of Science and Arts, University ofAhi Evran, 40200, Kirsehir, Turkey, M. Gaffaroglu(M.G. 30, 31).RESULTSThe diploid chromosome number in bothspecies is 2n=50. There were eight pairs of meta-centric, thirteen pairs of submetacentric, and fourpairs of subtelocentric to acrocentric chromosomesin the karyotypes of A. marmid and three pairs ofmetacentric, twelve pairs of submetacentric andten pairs of subtelocentric to acrocentric chromosomesin the karyotypes of C. macrostomus. No hetero-morphic sex chromosomes were detected in bothspecies. C-band analysis revealed that constitutiveheterochromatin was located at pericentromericregions of all chromosomes in both species. Besidethis, C-bands were observed on the short arms ofone or two pairs of submetacentric chromosomesin A. marmid and on the short arms of one or twopairs of submeta-subtelocentric chromosomes ofC. macrostomus. Heterochromatin blocks on thearms were bigger and more prominent. There weredifferences in the distribution of C-bands withinthe two species. That was to say those C-bandpatterns within species were heteromorphic. Inother words there were C-bands on one pairs ofchromosomes of some specimens and on onepairs of chromosomes on the others. Pericentric C-band regions were small and weakly dyed. In factweak colour of heterochromatin region wascharacteristic for both species. C-band patternswere similar in the two species. That was thelocality and the amounts of heterochromatin intwo species were almost similar. On the otherhand there were similarities between NORlocation and C-band patterns.DISCUSSIONC-bands indicate the presence of constitutiveheterochromatin associated with ribosomal genes.Similar results were obtained by Boron 14.However, there are no report of C-banding studyon A. marmid and C. macrostomus. No significantdifferences have been observed between sexesboth in the amount and in the location ofheterochromatin. C-banded metaphases are shownin Fig.1 and 2. As shown, the amount ofheterochromatin in these two species wasconsiderably less than euchromatin, similar resultshave been obtained by Rabova et al.10. However,reported that the amount of heterochromatin wasup to 60-70 % of the total chromosomes in NorthAmerican Cyprinids 8. The amount of heterochromatin is of interest toour long terms goals of understanding thechromosomal evolution and cytotaxonomy. Ingeneral extensive heterochromatin contentindicates extensive potential to vary or vice-versa.From this point of view, we are far fromsatisfaction to evaluate evolutionary mechanismC-band pattern of chromosomal speciation in fishdue to inadequate amount of data. Gül et al.7 in Chalcalburnus tarichi (2n=50) andRabova et al.10 in Vimba vimba (2n=50) and in V.elongate reported that there were small hetero-Constitutive heterochromatin in...170chromatic blocks in pericentromeric regions of allchromosome. In addition Rabova et al. reported inV. vimba that the largest subtelo-acrocentric pairof chromosomes showed size heteromorphism fordistal blocks of heterochromatin and all thechromosomes in variably posses is C-bands aroundthe centromeres 10. These results are in agreementwith our results in the present study.Most species invariably possess C-bands at oraround the centromeres (procentric) and frequentlyat the chromosome tips (telomeric). C-bands mayalso be found along chromosome arms (interstitial)and as entirely heterochromatic short arms ofacrocentric chromosomes. The variation in such“short-arm” heterochromatin was particularlyimpressive in the rodent genera 8. It was clear frominspection of the karyograms that many chromosomesin both species were very similar in relative size,centromer position, and C-banding. This wasespecially true for most of the chromosomes withshort-arm heterochromatin. In general chromosome arm number variationwhich differentiate species in both genera. Theextensive heterochromatin content indicates aconsiderable potential to vary. Many naturalpopulations contain substantial amounts of telomericand interstitial heterochromatin which exist in apolymorphic state. Crossover events may occuraway from these heterochromatin blocks 15. Thus,the immediate effect of this is to modify therelative frequency of gene combination andresulting differentiation of related species.Actually it has been possible to demonstrate theeffect of heterochromatin on crossing-over bydifferent ways i.e. i. By the use of classic genemarkers in an organism. ii. By the use of inversionmarkers. iii. By an analysis of chiasmic pattern. iv.By PCR.It has long been evident that the amount ofheterochromatin was not necessarily constant fromindividual to individual within a species.However, it is important to give detailed attentionto expensive heterochromatic variation nowrecognized in many natural populations. Thisvariation extends all the way from large, C-bandedblocks to the level of individual polytene bands.Increases and decreases in C-band material appearto be common in most species.REFERENCES1. Kuru M: Türkiye içsu baliklarinin son sistematik durumu.Gazi Üniv Gazi Eğitim Fak Derg, 24 (3): 1-21, 2004.2. Çolak A, Sezgin İ, Süngü SY: Sazangiller familyasina(Cyprinidae) ait Beni baliğinda (Cyprinion macrostomumHeckel, 1843) kromozomal araştirmalar. Doğa Türk BiyolDerg, 9 (2): 193-195, 1985.3. Ergene S, Kuru M, Çavaş T: Barbus plebejus lacerta(Heckel, 1843)’nTn Karyolojik Analizi. II. UluslararasTKTzTlTrmak Fen Bilimleri Kongresi, 20-22 MayTs, KTrTkkale,Türkiye, 1998.4. KHlHç-Demirok N, Ünlü E: Karyotypes of Cyprinid FishCapoeta trutta and Capoeta capoeta umbla (Cyprinidae) fromthe Tigris River. Tr J of Zool, 25, 389-395, 2001.5.Gül S, Çolak A, Sezgin İ: Gümüş BalTğT’nda (ChalcalburnusGAFFAROĞLU, YÜKSEL171Fig. 1. C-banding pattern of Acanthobrama marmidŞekil 1. Acanthobrama marmid’de C-band kalıbıFig. 2. C-banding pattern of Cyprinion macrostomusŞekil 2. Cyprinion macrostomus’da C-band kalıbımossulensis Heckel, 1843) karyotip analizi. Doğa Türk, BiyolDerg, 24, 657-662, 2000.6. Gaffaroglu M: Karakaya Baraj Gölünde yaşayan Cyprinidaefamilyasina ait bazi türlerin karyolojik analizleri. DoktoraTezi, İnönü Üniversitesi, Türkiye, 2003.7. Gül S, Çolak A, Sezgin İ, Kaloğlu B: Van Gölünde endemikolan inci kefali (Chalcalburnus tarichi Pallas, 1811)kromozomlarTnTn C, G ve restriksiyon endonükleazlar (AluI,NheI, HaeIII, MboI, HinfI) ile bantlanmasT. Tr J Vet Anim Sci,27, 1293-1298, 2003.8. Gold JR, Amemiya CT, Ellison JR: Chromosomalheterochromatin differentiation in North American CyprinidFishes. Cytologia, 51, 557-566, 1986.9. Ueda T, Naoi H, Arai R: Flexibility on the karyotypeevolution in bitterlings (Pisces, Cyprinidae). Genetica, 111,423-432, 2001.10. Rábová M, Ráb P, Ozouf-Costaz C, Ene C, Wanzeböck J: Comparative cytogenetics and chromosomal characteristics ofribosomal DNA in the fish genus Vimba (Cyprinidae).Genetica, 118, 83-91, 2003.11. Collares-Pereira MJ: First Internatioal Workshop on FishCytogenetic Techniques, Concarneau, France, 14-24September 1992.12. Sumner AT: A simple technique for demonstratingcentromeric heterochromatin. Exp Cell Res, 75, 304-306,1972.13. Levan A, Fredga K, Sandberg AA: Nomenclature forcentromeric position on chromosomes. Hereditas, 52, 201-220, 1964.14. Boroń A: Banded karyotype of spined loach Cobitis taeniaand triploid Cobitis from Poland. Genetica, 105, 293-300,1999.15. John B, Miklas, GL: Functional aspects of satellite DNAand heterochromatin. Int Rev Cytol, 58, 1-114, 1979.Constitutive heterochromatin in...172

Constitutive heterochromatin in Acanthobrama marmid and Cyprinion macrostomus (Osteichthyes, Cyprinidae)

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