Extraordinary and extensive karyotypic variation: A 48-fold range in chromosome number in the gall-inducing scale insect Apiomorpha (Hemiptera: Coccoidea: Eriococcidae)

Genome ◽  
2000 ◽  
Vol 43 (2) ◽  
pp. 255-263 ◽  
Author(s):  
Lyn G Cook
Keyword(s):  
Chromosome Number ◽  
Chromosomal Rearrangements ◽  
Chromosomal Polymorphism ◽  
Chromosomal Evolution ◽  
Scale Insect ◽  
Closely Related Species ◽  
Host Genus ◽  
Species Complexes ◽  
Species Groups ◽  
Karyotypic Variation

Chromosome number reflects strong constraints on karyotype evolution, unescaped by the majority of animal taxa. Although there is commonly chromosomal polymorphism among closely related taxa, very large differences in chromosome number are rare. This study reports one of the most extensive chromosomal ranges yet reported for an animal genus. Apiomorpha Rübsaamen (Hemiptera: Coccoidea: Eriococcidae), an endemic Australian gall-inducing scale insect genus, exhibits an extraordinary 48-fold variation in chromosome number with diploid numbers ranging from 4 to about 192. Diploid complements of all other eriococcids examined to date range only from 6 to 28. Closely related species of Apiomorpha usually have very different karyotypes, to the extent that the variation within some species- groups is as great as that across the entire genus. There is extensive chromosomal variation among populations within 17 of the morphologically defined species of Apiomorpha indicating the existence of cryptic species-complexes. The extent and pattern of karyotypic variation suggests rapid chromosomal evolution via fissions and (or) fusions. It is hypothesized that chromosomal rearrangements in Apiomorpha species may be associated with these insects' tracking the radiation of their speciose host genus, Eucalyptus. Key words: Apiomorpha, cytogenetics, chromosomal evolution, holocentric.

scholarly journals Chromosomal Evolution in the Lizard Genus Varanus (Reptilia)

1975 ◽  
Vol 28 (1) ◽  
pp. 89 ◽  
Author(s):  
Max Kinga ◽  
Dennis King
Keyword(s):  
Chromosome Number ◽  
Pericentric Inversion ◽  
Sex Chromosome ◽  
Chromosomal Rearrangements ◽  
Chromosomal Evolution ◽  
Size Groups ◽  
Sex Chromosome System

The karyotypes have been determined of 16 of the 32 species of the genus Varanus, including animals from Africa, Israel, Malaya and Australia. A constant chromosome number of 2n = 40 was observed. The karyotype is divided into eight pairs of large chromosomes and 12 pairs of microchromosomes. A series of chromosomal rearrangements have become established in both size groups of the karyotype and are restricted to centromere shifts, probably caused by pericentric inversion. Species could be placed in one of six distinct karyotype groups which are differentiated by these rearrangements and whose grouping does not always correspond with the current taxonomy. An unusual sex chromosome system of the ZZjZW type was present in a number of the species examined.

scholarly journals Centromere Repeats: Hidden Gems of the Genome

Genes ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 223 ◽  
Author(s):  
Gabrielle Hartley ◽  
Rachel O’Neill
Keyword(s):  
Transposable Elements ◽  
De Novo ◽  
Chromosomal Rearrangements ◽  
Repetitive Sequences ◽  
Chromosomal Evolution ◽  
Satellite Dnas ◽  
Integral Role ◽  
Chromosomal Breakpoints ◽  
Karyotypic Variation ◽  
Species Specific

Satellite DNAs are now regarded as powerful and active contributors to genomic and chromosomal evolution. Paired with mobile transposable elements, these repetitive sequences provide a dynamic mechanism through which novel karyotypic modifications and chromosomal rearrangements may occur. In this review, we discuss the regulatory activity of satellite DNA and their neighboring transposable elements in a chromosomal context with a particular emphasis on the integral role of both in centromere function. In addition, we discuss the varied mechanisms by which centromeric repeats have endured evolutionary processes, producing a novel, species-specific centromeric landscape despite sharing a ubiquitously conserved function. Finally, we highlight the role these repetitive elements play in the establishment and functionality of de novo centromeres and chromosomal breakpoints that underpin karyotypic variation. By emphasizing these unique activities of satellite DNAs and transposable elements, we hope to disparage the conventional exemplification of repetitive DNA in the historically-associated context of ‘junk’.

scholarly journals Rapid chromosomal evolution in the bush-cricket Gonatoxia helleri Hemp, 2016 (Orthoptera, Phaneropterinae)

2020 ◽  
Vol 14 (3) ◽  
pp. 417-435 ◽  
Author(s):  
Elżbieta Warchałowska-Śliwa ◽  
Beata Grzywacz ◽  
Anna Maryańska-Nadachowska ◽  
Klaus-Gerhard Heller ◽  
Claudia Hemp
Keyword(s):  
Chromosome Number ◽  
18S Rdna ◽  
Chromosomal Polymorphism ◽  
Chromosomal Evolution ◽  
Chromosome Morphology ◽  
Telomeric Sequences ◽  
C Banding ◽  
Interstitial Telomeric Sequences ◽  
Rdna Loci ◽  
Bush Crickets

Gonatoxia helleri Hemp, 2016 is one of the most widespread bush-crickets of the genus Gonatoxia Karsch, 1889 in East Africa. This species with seven large chromosomes (2n♂ = 7) differs from other representatives of the genus Gonatoxia drastically by its reduced chromosome number, the asymmetrical karyotype including karyomorphs rarely found in tettigoniids, as well as in irregularities in the course of meiosis. To better understand the origin of such an exceptional karyotype, chromosomes of 29 specimens from four populations/localities were studied using classical techniques, such as C-banding, silver impregnation, fluorochrome double staining and fluorescence in situ hybridization (FISH) technique with 18S rDNA and (TTAGG)n telomeric probes. FISH showed many 18S rDNA loci as well as interstitial telomeric sequences, where chromosome morphology varied in these components in terms of quantity and distribution. The 18S rDNA loci coincided with active NORs and C-banding patterns. We suggest that a combination of Robertsonian rearrangements and/or multiple common tandem fusions involving the same chromosomes contributed to the formation of this karyotype/karyomorphs. The results are the first step towards a better understanding of chromosomal reorganization and evolution within the genus Gonatoxia. Low chromosome number, together with the incidence of chromosomal polymorphism that is higher in G. helleri than previously reported in bush-crickets, implies that this species can be a valuable new model for cytogenetic and speciation studies. Our findings suggest that chromosomal translocations lead to diversification and speciation in this species and could be the driving force of adaptive radiation.

scholarly journals Comparative cytogenetics of Serrasalmidae (Teleostei: Characiformes): The relationship between chromosomal evolution and molecular phylogenies

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258003
Author(s):  
Ramon Marin Favarato ◽  
Leila Braga Ribeiro ◽  
Alber Campos ◽  
Jorge Ivan Rebelo Porto ◽  
Celeste Mutuko Nakayama ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Chromosomal Rearrangements ◽  
5S Rdna ◽  
Chromosomal Evolution ◽  
Comparative Cytogenetics ◽  
Molecular Cytogenetic ◽  
The Family ◽  
Identification Of Species ◽  
Molecular Cytogenetic Techniques ◽  
The Relationship

Serrasalmidae has high morphological and chromosomal diversity. Based on molecular hypotheses, the family is currently divided into two subfamilies, Colossomatinae and Serrasalminae, with Serrasalminae composed of two tribes: Myleini (comprising most of pacus species) and Serrasalmini (represented by Metynnis, Catoprion, and remaining piranha’s genera). This study aimed to analyze species of the tribes Myleini (Myloplus asterias, M. lobatus, M. rubripinnis, M. schomburgki, and Tometes camunani) and Serrasalmini (Metynnis cuiaba, M. hypsauchen, and M. longipinnis) using classical and molecular cytogenetic techniques in order to understand the chromosomal evolution of the family. The four species of the genus Myloplus and T. camunani presented 2n = 58 chromosomes, while the species of Metynnis presented 2n = 62 chromosomes. The distribution of heterochromatin occurred predominantly in pericentromeric regions in all species. Tometes camunani and Myloplus spp. presented only one site with 5S rDNA. Multiple markers of 18S rDNA were observed in T. camunani, M. asterias, M. lobatus, M. rubripinnis, and M. schomburgkii. For Metynnis, however, synteny of the 18S and 5S rDNA was observed in the three species, in addition to an additional 5S marker in M. longipinnis. These data, when superimposed on the phylogeny of the family, suggest a tendency to increase the diploid chromosome number from 54 to 62 chromosomes, which occurred in a nonlinear manner and is the result of several chromosomal rearrangements. In addition, the different karyotype formulas and locations of ribosomal sequences can be used as cytotaxonomic markers and assist in the identification of species.

scholarly journals Revision of the pollen beetle genus Meligethes (Coleoptera: Nitidulidae)

2014 ◽  
Vol 46 (1-2) ◽  
pp. 19 ◽  
Author(s):  
Paolo Audisio ◽  
Simone Sabatelli ◽  
Josef Jelìnek
Keyword(s):  
Taxonomic Revision ◽  
Central China ◽  
Pollen Beetle ◽  
Sw China ◽  
Species Complexes ◽  
Western Palearctic ◽  
Specific Rank ◽  
Species Groups ◽  
Available Information ◽  
First Time

A taxonomic revision of members of the genus <em>Meligethes</em> Stephens, 1830 is carried out. Taxonomic and distributional notes are provided on fiftythree <em>Meligethes</em> species, mostly known from the Eastern Palearctic and marginally from the Western Palearctic and the Oriental Regions. Among these, twentythree new species of <em>Meligethes</em> are diagnosed, figured and described: <em>M</em>. <em>argentithorax</em> sp. n. (Central China: Shaanxi, Shanxi), <em>M</em>. <em>aurantirugosus</em> sp. n. (Nepal),<em> M. aureolineatus</em> sp. n. (Central China: Sichuan), <em>M. aurifer</em> sp. n. (Central China: Shaanxi, Shanxi), <em>M. brassicogethoides</em> sp. n. (SW China: Yunnan), <em>M. clinei</em> sp. n. (SW China: Yunnan), <em>M. elytralis</em> sp. n. (Central China: Sichuan), <em>M. ferruginoides</em> sp. n. (Central China: Sichuan), <em>M.</em> <em>cinereoargenteus</em> sp. n. (Central China: Sichuan), <em>M. henan</em> sp. n. (Central China: Henan), <em>M. luteoornatus</em> sp. n. (SW China: Yunnan), <em>M. marmota</em> sp. n. (Nepal), <em>M. nivalis</em> sp. n. (SW and central China: Xizang and Chongqing), <em>M. martes</em> sp. n. (Central China: Shaanxi, Shanxi, Sichuan), <em>M. nigroaeneus</em> sp. n. (SW China: Yunnan), <em>M. occultus</em> sp. n. (SW China: Yunnan), <em>M</em>. <em>pseudochinensis</em> sp. n. (Central China: Hubei), <em>M. pseudopectoralis</em> sp. n. (SW China: Yunan),<em> M. schuelkei</em> sp. n. (Central China: Sichuan, Shaanxi), <em>M. simulator</em> sp. n. (Central-N China: Shanxi), <em>M. stenotarsus</em> sp. n. (SW China: Yunnan, Xizang), <em>M. tryznai</em> sp. n. (SW China: Yunnan), and <em>M. volkovichi</em> sp. n. (SW China: Yunnan). Revaluations at specific rank from synonymy are introduced for <em>Meligethes lutra</em> Solsky 1860, and for <em>M. melleus</em> Grouvelle, 1908. Three new synonymies are established: <em>Meligethes brevipilus</em> Kirejtshuk, 1980 = <em>M. auripilis</em> Reitter, 1889 (syn. n.), <em>Meligethes zakharenkoi</em> Kirejtshuk, 2005 = <em>M. shirakii</em> Sadanari Hisamatsu, 1956 (syn. n.), and <em>Meligethes shirozui</em> Sadanari Hisamatsu, 1965 =<em> M. wagneri</em> Rebmann, 1956 (syn. n.). Complete redescriptions are given for <em>Meligethes binotatus</em> Grouvelle, 1894, <em>M. castanescens</em> Grouvelle, 1903, <em>M. ferrugineus</em> Reitter, 1873, and <em>M. melleus</em> Grouvelle, 1908. The male of <em>Meligethes lloydi</em> Easton, 1968, is described and figured for the first time. The female genitalia of <em>Meligethes auricomus</em> Rebmann, 1956, <em>M. cinereus</em> Jelínek, 1978, and <em>M. griseus</em> Jelínek, 1978 are described and figured for the first time. Available information on insect-host-plant relationships and ecology are summarized for each species; probably all are associated as larvae with flowers of Rosaceae, chiefly of members of the closely related genera <em>Rosa</em> L., <em>Rubus</em> L., <em>Prunus</em> L., and <em>Crataegus</em> Tourn. ex L. All treated species are grouped in two here revaluated subgenera (<em>Meligethes</em> s.str. and <em>Odonthogethes</em> Reitter, 1871), and tentatively grouped also in species-groups and (when necessary) species-complexes, based on their morphology.

scholarly journals Loss of centromere function drives karyotype evolution in closely related Malassezia species

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Sundar Ram Sankaranarayanan ◽  
Giuseppe Ianiri ◽  
Marco A Coelho ◽  
Md Hashim Reza ◽  
Bhagya C Thimmappa ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Histone H3 ◽  
Chromosome Breakage ◽  
Ancestral State ◽  
Chromosome Fusion ◽  
Closely Related Species ◽  
Malassezia Species ◽  
Malassezia Globosa ◽  
Centromere Inactivation ◽  
Genome Assemblies

Genomic rearrangements associated with speciation often result in variation in chromosome number among closely related species. Malassezia species show variable karyotypes ranging between six and nine chromosomes. Here, we experimentally identified all eight centromeres in M. sympodialis as 3–5-kb long kinetochore-bound regions that span an AT-rich core and are depleted of the canonical histone H3. Centromeres of similar sequence features were identified as CENP-A-rich regions in Malassezia furfur, which has seven chromosomes, and histone H3 depleted regions in Malassezia slooffiae and Malassezia globosa with nine chromosomes each. Analysis of synteny conservation across centromeres with newly generated chromosome-level genome assemblies suggests two distinct mechanisms of chromosome number reduction from an inferred nine-chromosome ancestral state: (a) chromosome breakage followed by loss of centromere DNA and (b) centromere inactivation accompanied by changes in DNA sequence following chromosome–chromosome fusion. We propose that AT-rich centromeres drive karyotype diversity in the Malassezia species complex through breakage and inactivation.

Psidium guajava L.: taxonomy, relatives and possible origin.

2021 ◽  
pp. 1-21
Author(s):  
Leslie R. Landrum
Keyword(s):  
Chromosome Number ◽  
Genome Size ◽  
Morphological Characteristics ◽  
Psidium Guajava ◽  
Medicinal Uses ◽  
Species Complexes

Abstract This chapter focuses on the taxonomy and geography of guava (Psidium guajava). Information is given on geography, morphological characteristics, chromosome number and genome size, phytochemistry and medicinal uses, closest relatives, and keys to species complexes.

A new species of Gomesa (Oncidiinae, Orchidaceae) from inselbergs in Brazilian caatinga: morphological and karyological evidence

Phytotaxa ◽  
2018 ◽  
Vol 374 (2) ◽  
pp. 147 ◽  
Author(s):  
JOEL M. P. CORDEIRO ◽  
FELIPE NOLLET ◽  
MARIA TERESA BURIL ◽  
MARK W. CHASE ◽  
LEONARDO P. FELIX
Keyword(s):  
New Species ◽  
Chromosome Number ◽  
Geographical Distribution ◽  
Related Species ◽  
Species Differences ◽  
Flower Morphology ◽  
Closely Related Species ◽  
Restricted Distribution ◽  
A New Species

We describe a new species of Gomesa (Oncidiinae, Orchidaceae), Gomesa caatingana, with restricted distribution on caatinga inselbergs in Paraíba and Pernambuco States, Brazil. Morphological and karyological characters of the new species were compared with those of Gomesa flexuosa, which is morphologically the most closely related species. Differences in geographical distribution, habit, flower morphology and chromosome number support description of this new species.

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