Telomeric heterochromatin and meiotic recombination in three species of Coleoptera (Dorcadion olympicum Ganglebauer, Stephanorrhina princeps Oberthür and Macraspis tristis Laporte) Anne-Marie Dutrillaux, Bernard Dutrillaux To cite this version: Anne-Marie Dutrillaux, Bernard Dutrillaux. Telomeric heterochromatin and meiotic recombina- tion in three species of Coleoptera (Dorcadion olympicum Ganglebauer, Stephanorrhina princeps Oberthür and Macraspis tristis Laporte). Caryologia, Firenze University Press, 2019, 72 (2), pp.63-68. 10.13128/cayologia-194. hal-02968165 HAL Id: hal-02968165 https://hal.archives-ouvertes.fr/hal-02968165 Submitted on 15 Oct 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Firenze University Press Caryologia www.fupress.com/caryologia International Journal of Cytology, Cytosystematics and Cytogenetics Telomeric heterochromatin and meiotic recombination in three species of Coleoptera Citation: A.-M. Dutrillaux, B. Dutrillaux (2019) Telomeric heterochromatin and (Dorcadion olympicum Ganglebauer, meiotic recombination in three species of Coleoptera (Dorcadion olympicum Stephanorrhina princeps Oberthür and Ganglebauer, Stephanorrhina prin- ceps Oberthür and Macraspis tristis Macraspis tristis Laporte) Laporte). Caryologia 72(2): 63-68. doi: 10.13128/cayologia-194 Published: December 5, 2019 Anne-Marie Dutrillaux, Bernard Dutrillaux* Copyright: © 2019 A.-M. Dutrillaux, Systématique, Évolution, Biodiversité, ISYEB - UMR 7205 – CNRS MNHN UPMC B. Dutrillaux. This is an open access, EPHE, Muséum National d’Histoire Naturelle, Sorbonne Universités, 57 rue Cuvier CP50 peer-reviewed article published by F-75005, Paris, France Firenze University Press (http://www. *Corresponding author: [email protected] fupress.com/caryologia) and distributed under the terms of the Creative Com- mons Attribution License, which per- Abstract. Centromeres are generally embedded in heterochromatin, which is assumed mits unrestricted use, distribution, and to have a negative impact on meiotic recombination in adjacent regions, a condition reproduction in any medium, provided required for the correct segregation of chromosomes at anaphase I. At difference, tel- the original author and source are credited. omeric and interstitial regions rarely harbour large heterochromatic fragments. We observed the presence at the heterozygote status of heterochromatin in telomere region Data Availability Statement: All rel- of some chromosomes in 3 species of Coleoptera: Dorcadion olympicum; Stephanor- evant data are within the paper and its rhina princeps and Macraspis tristis. This provided us with the opportunity to study the Supporting Information files. relationship between heterochromatin, chiasma location and meiotic recombination independently from the proximity of centromeres in this order of insects. In acrocen- Competing Interests: The Author(s) declare(s) no conflict of interest. tric chromosomes, the presence of heterochromatin in telomere region of the long arm displaces recombination near the centromere. In sub-metacentrics, recombination is almost always restricted to the other arm. This at distance effect of heterochromatin may deeply influence genetic drift. Keywords. C-banded, telomeric heterochromatin, meiosis, recombination, Coleoptera. INTRODUCTION In almost all living organisms, centromeres are surrounded by hetero- chromatin, which harbours repetitive DNA (Nakaseko et al. 1986), whose function is not yet completely understood. In cells in mitotic growth, het- erochromatin represses transcription and expression of genes located into it (Grewal and Jia 2007). During meiosis of most living organisms, recom- bination is necessary for the correct chromosome segregation at anaphase I, but it does not occur in heterochromatin. Consequently, recombination is repressed in centromeric regions, which harbour heterochromatin. In Schizo- saccharomyces pombe, it was found to be approximately 200 times less in het- Caryologia. International Journal of Cytology, Cytosystematics and Cytogenetics 72(2): 63-68, 2019 ISSN 0008-7114 (print) | ISSN 2165-5391 (online) | DOI: 10.13128/cayologia-194 64 Anne-Marie Dutrillaux, Bernard Dutrillaux erochromatin than in the genome-wide average (Eller- located on one arm displaces recombination to the other meier et al. 2010). A current interpretation is that recom- arm. Thus, heterochromatin can suppress recombination bination, thus chiasma formation in centromeric region, on a whole arm and influence meiotic recombination at would lead to abnormal chromosome segregation (Lynn much larger distance than it was generally thought. et al. 2004). Thus, a function of centromeric heterochro- matin would be to displace recombination far from the centromeres and allow the correct chromosome segre- MATERIAL AND METHODS gation. Large and variable amounts of heterochromatin are present in the karyotype of many animals belonging Three examples belonging to three different families to various taxonomic groups, but their position is not at or sub-families were found among about 400 species of random: frequently juxta-centromeric and rarely inter- Polyphagan beetles: stitial or terminal. In mammals, a wellknown example Dorcadion olympicum Ganglebauer 1882 (Ceram- of terminal heterochromatin is that of the Hedgehog bycidae: Lamiinae: Dorcadionini). Two specimens were (Insectivora) in the karyotype of which 2 to 4 chromo- captured in May 2014 in Eastern Greece, near Alexan- some pairs are involved. However, the heterochromatic droupolis (40° 50’57”N and 25°52’46”E). blocks are not strictly terminal because NORs (Nucleo- Stephanorrhina princeps Oberthür 1880 (Scarabaei- lar Organizer Regions) are located at their extremity dae: Cetoninae: Goliathini). Two specimens of African (Mandhal 1979). It was noticed that no meiotic recom- origin (Malawi) were obtained in September2007 from a bination occurred in and at proximity of heterochroma- private breeding. tin (Natarajan and Gropp 1971). The same particularities Macraspis tristis Laporte 1840 (Scarabaeidae: Ruteli- were observed in the Primate Cebus capucinus (Dutril- nae: Rutelini). Eight adult specimenswere obtained in laux 1979) but such examples remain rare. In insects, March 2008 from grubs captured in Guadeloupe (Basse- terminal heterochromatin was observed in acrocentric Terre, near Deshayes 16°18’00”N and 61°47’00”W) in chromosomes of several species of grasshoppers (John December 2006. and King 1982, 1985, Torre et al. 1985). These authors Chromosome preparations of cells at various stages attributed the displacement of chiasmata to proximal of meiosis were obtained as described (Dutrillaux and position to the presence of terminal heterochromatin. In Dutrillaux 2009, Dutrillaux et al. 2010). Proliferating Coleoptera, large heterochromatic fragments are com- cells obtained from either eggs, testes or mid gut were monly seen in most families (Juan and Petitpierre, 1989, processed as described. Chromosomes were Giemsa Correa et al., 2008, Dutrillaux and Dutrillaux, 2016), stained and further silver stained for localization of the but almost always in the centromere region, as in other Nucleolus Organizer Region (NOR) and/or C-banded taxonomic groups. This preferential location may result for localization of heterochromatin. Image capture and from the amplification of DNA repeated sequence sur- karyotyping were performed using IKAROS software rounding centromeres, as shown for α satellite sequences (Metasystems, Germany). Chromosome nomenclature: (Rudd et al. 2006, Shepelev et al. 2009). As it will be dis- to avoid ambiguous interpretations, we will call acro- cussed, the correct segregation of chromosomes at meio- centric all chromosomes with a single euchromatic arm, sis may also depend on the embedding of centromeres in whatever the size of the heterochromatin (generally heterochromatin. Displacement of heterochromatin from C-banded) forming the other arm. Chromosomes with centromere regions to intercalary or terminal regions euchromatin (not C-banded) on both arms are either would necessitate secondary events, but terminal het- metacentric or sub-metacentric. We will focus on chro- erochromatin may have other origins. It will be also dis- mosomes with large heterochromatic blocks distally cussed that the presence of heterochromatin in telomeric attached to euchromatic arms. position may not confer a selective advantage, by impos- ing meiotic constraints. Among hundreds of species of Coleoptera we studied, karyotypes with large amounts RESULTS of heterochromatin in terminal position were rarely observed. We confirm that heterochromatin terminally Dorcadion olympicum located on the long arm of acrocentrics may not decrease recombination, but simply displaces it near to the cen- The mitotic male karyotype is composed of 24 chro- tromere, usually considered as a cold region (Mahtani mosomes. Pairs 3 and 5 are sub-metacentric and all and Willard 1998). In addition, we show that in non- other autosomes are acrocentric. The X chromosome is acrocentric chromosomes, heterochromatin