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Patterns of geographic variation of thermal adapted candidate genes in Drosophila subobscura sex chromosome arrangements. BMC Evol Biol 2018; 18:60. [PMID: 29699488 PMCID: PMC5921438 DOI: 10.1186/s12862-018-1178-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 04/11/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The role of chromosomal arrangements in adaptation is supported by the repeatable clinal variation in inversion frequencies across continents in colonizing species such as Drosophila subobscura. However, there is a lack of knowledge on the genetic variation in genes within inversions, possibly targets of climatic selection, across a geographic latitudinal gradient. In the present study we analysed four candidate loci for thermal adaptation, located close to the breakpoints, in two chromosomal arrangements of the sex (A) chromosome of Drosophila subobscura with different thermal preferences. Individual chromosomes with A2 (the inverted arrangement considered warm adapted) or AST (the standard ancestral arrangement considered cold adapted) were sequenced across four European localities at varying latitudes, up to ~ 2500 Kms apart. RESULTS Importantly, we found very low differentiation for each specific arrangement across populations as well as no clinal patterns of genomic variation. This suggests wide gene exchange along the cline. Differentiation between the sex chromosome arrangements was significant in the two more proximal regions relative to the AST orientation but not in the distal ones, independently of their location inside or outside the inversion. This can be possibly due to variation in the levels of gene flux and/or selection acting in these regions. CONCLUSIONS Gene flow appears to have homogenized the genetic content within-arrangement at a wide geographical scale, despite the expected diverse selective pressures in the specific natural environments of the different populations sampled. It is thus likely that the inversion frequency clines in this species are being maintained by local adaptation in face of gene flow. The differences between arrangements at non-coding regions might be associated with the previously observed differential gene expression in different thermal regimes. Higher resolution genomic scans for individual chromosomal arrangements performed over a large environmental gradient are needed to find the targets of selection and further elucidate the adaptive mechanisms maintaining chromosomal inversion polymorphisms.
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Morán T, Fontdevila A. Genome-wide dissection of hybrid sterility in Drosophila confirms a polygenic threshold architecture. J Hered 2014; 105:381-96. [PMID: 24489077 DOI: 10.1093/jhered/esu003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To date, different studies about the genetic basis of hybrid male sterility (HMS), a postzygotic reproductive barrier thoroughly investigated using Drosophila species, have demonstrated that no single major gene can produce hybrid sterility without the cooperation of several genetic factors. Early work using hybrids between Drosophila koepferae (Dk) and Drosophila buzzatii (Db) was consistent with the idea that HMS requires the cooperation of several genetic factors, supporting a polygenic threshold (PT) model. Here we present a genome-wide mapping strategy to test the PT model, analyzing serially backcrossed fertile and sterile males in which the Dk genome was introgressed into the Db background. We identified 32 Dk-specific markers significantly associated with hybrid sterility. Our results demonstrate 1) a strong correlation between the number of segregated sterility markers and males' degree of sterility, 2) the exchangeability among markers, 3) their tendency to cluster into low-recombining chromosomal regions, and 4) the requirement for a minimum number (threshold) of markers to elicit sterility. Although our findings do not contradict a role for occasional major hybrid-sterility genes, they conform more to the view that HMS primarily evolves by the cumulative action of many interacting genes of minor effect in a complex PT architecture.
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Affiliation(s)
- Tomás Morán
- the Grup de Biologia Evolutiva, Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
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Pegueroles C, Aquadro CF, Mestres F, Pascual M. Gene flow and gene flux shape evolutionary patterns of variation in Drosophila subobscura. Heredity (Edinb) 2013; 110:520-9. [PMID: 23321709 PMCID: PMC3656635 DOI: 10.1038/hdy.2012.118] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 10/11/2012] [Accepted: 12/17/2012] [Indexed: 12/12/2022] Open
Abstract
Gene flow (defined as allele exchange between populations) and gene flux (defined as allele exchange during meiosis in heterokaryotypic females) are important factors decreasing genetic differentiation between populations and inversions. Many chromosomal inversions are under strong selection and their role in recombination reduction enhances the maintenance of their genetic distinctness. Here we analyze levels and patterns of nucleotide diversity, selection and demographic history, using 37 individuals of Drosophila subobscura from Mount Parnes (Greece) and Barcelona (Spain). Our sampling focused on two frequent O-chromosome arrangements that differ by two overlapping inversions (OST and O(3+4)), which are differentially adapted to the environment as observed by their opposing latitudinal clines in inversion frequencies. The six analyzed genes (Pif1A, Abi, Sqd, Yrt, Atpα and Fmr1) were selected for their location across the O-chromosome and their implication in thermal adaptation. Despite the extensive gene flux detected outside the inverted region, significant genetic differentiation between both arrangements was found inside it. However, high levels of gene flow were detected for all six genes when comparing the same arrangement among populations. These results suggest that the adaptive value of inversions is maintained, regardless of the lack of genetic differentiation within arrangements from different populations, and thus favors the Local Adaptation hypothesis over the Coadapted Genome hypothesis as the basis of the selection acting on inversions in these populations.
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Affiliation(s)
- C Pegueroles
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Spain.
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Vela D, Guerreiro MPG, Fontdevila A. Adaptation of the AFLP technique as a new tool to detect genetic instability and transposition in interspecific hybrids. Biotechniques 2011; 50:247-50. [PMID: 21548908 DOI: 10.2144/000113655] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 02/23/2011] [Indexed: 11/23/2022] Open
Abstract
An adapted amplified fragment length polymorphism (AFLP) protocol is presented for detection of hybrid instability in the genome of interspecific hybrids between Drosophila buzzatii and D. koepferae species. Analyses of 15 AFLP instability markers (new bands detected in hybrids) show that up to 81% are the result of transposable element (TE) activity. Twenty TEs associated with AFLP instability markers have been detected by this method in backcross hybrids and segmental hybrids, demonstrating its validity in detecting transposition events occurring during the hybridization process. New insertions of Helena TE have been observed in the hybrid genome after hybridization of the TGTCG22 instability marker by FISH. The AFLP marker technique proved to be an efficient method that improves upon traditional and bioinformatic tools previously used to detect TE mobilization. This newly adapted AFLP protocol may also be applied to a large number of organisms outside the Drosophila genus, making it of interest to evolutionary and population genetic researchers working with species where the knowledge of the genome is scarce.
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Affiliation(s)
- Doris Vela
- Grup de Biologia Evolutiva, Departament de Genética i Microbiología, Universitat Autonoma de Barcelona, Bellaterra, Barcelona, Spain
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Estimating genetic correlations based on phenotypic data: a simulation-based method. J Genet 2011; 90:51-8. [PMID: 21677389 DOI: 10.1007/s12041-011-0021-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Knowledge of genetic correlations is essential to understand the joint evolution of traits through correlated responses to selection, a difficult and seldom, very precise task even with easy-to-breed species. Here, a simulation-based method to estimate genetic correlations and genetic covariances that relies only on phenotypic measurements is proposed. The method does not require any degree of relatedness in the sampled individuals. Extensive numerical results suggest that the propose method may provide relatively efficient estimates regardless of sample sizes and contributions from common environmental effects.
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Frydenberg J, Barker JSF, Loeschcke V. Characterization of the shsp genes in Drosophila buzzatii and association between the frequency of Valine mutations in hsp23 and climatic variables along a longitudinal gradient in Australia. Cell Stress Chaperones 2010; 15:271-80. [PMID: 19806471 PMCID: PMC2866996 DOI: 10.1007/s12192-009-0140-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 08/20/2009] [Accepted: 08/20/2009] [Indexed: 10/20/2022] Open
Abstract
The small heat shock gene (shsp) cluster of Drosophila buzzatii was sequenced and the gene order and DNA sequence were compared with those of the shsps in Drosophila melanogaster. The D. buzzatii shsp cluster contains an inversion and a duplication of hsp26. A phylogenetic tree was constructed based on hsp26 genes from several Drosophila species of the Sophophora and Drosophila subgenera. The tree shows first a separation of the Sophophora and the Drosophila subgenera and then the Drosophila subgenus is divided into the Hawaiian Drosophila and the repleta/virilis groups. Only the latter contain a duplicated hsp26. Comparing the gene organisation of the shsp cluster shows that all the Drosophila subgenus species contain the inversion. Putative heat shock elements (HSE) were found in the promoters of all the shsp and putative regulator elements for tissue specific expression were found in the promoter of hsp23, hsp27 and one of the hsp26 genes. hsp23 was found to be polymorphic for four non-synonymous changes that all lead to exchange of a Valine. The duplicated hsp26 gene in D. buzzatii (phsp26) was polymorphic for two non-synonymous changes. The allele frequencies of these variants were determined in nine D. buzzatii populations covering most of its distribution in Australia using high-resolution melting curves. The allele frequencies of one of the hsp23 variants showed a significant linear regression with longitude and the pooled frequency of the four Valine changes of hsp23 in the nine populations showed a significant linear regression with longitude and with a composite measure of climatic variables.
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Affiliation(s)
- Jane Frydenberg
- Department of Biological Sciences, Ecology and Genetics, University of Aarhus, Ny Munkegade, Bldg. 1540, 8000, Aarhus C, Denmark.
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Gunderina LI, Kiknadze II, Golygina VV, Butler MG. Differentiation of chromosome banding sequence pools and genomic dna in Holarctic natural populations of Chironomus entis Shobanov (Diptera, Chironomidae). RUSS J GENET+ 2009. [DOI: 10.1134/s1022795409120023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Delprat A, Negre B, Puig M, Ruiz A. The transposon Galileo generates natural chromosomal inversions in Drosophila by ectopic recombination. PLoS One 2009; 4:e7883. [PMID: 19936241 PMCID: PMC2775673 DOI: 10.1371/journal.pone.0007883] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Accepted: 10/01/2009] [Indexed: 11/25/2022] Open
Abstract
Background Transposable elements (TEs) are responsible for the generation of chromosomal inversions in several groups of organisms. However, in Drosophila and other Dipterans, where inversions are abundant both as intraspecific polymorphisms and interspecific fixed differences, the evidence for a role of TEs is scarce. Previous work revealed that the transposon Galileo was involved in the generation of two polymorphic inversions of Drosophila buzzatii. Methodology/Principal Findings To assess the impact of TEs in Drosophila chromosomal evolution and shed light on the mechanism involved, we isolated and sequenced the two breakpoints of another widespread polymorphic inversion from D. buzzatii, 2z3. In the non inverted chromosome, the 2z3 distal breakpoint was located between genes CG2046 and CG10326 whereas the proximal breakpoint lies between two novel genes that we have named Dlh and Mdp. In the inverted chromosome, the analysis of the breakpoint sequences revealed relatively large insertions (2,870-bp and 4,786-bp long) including two copies of the transposon Galileo (subfamily Newton), one at each breakpoint, plus several other TEs. The two Galileo copies: (i) are inserted in opposite orientation; (ii) present exchanged target site duplications; and (iii) are both chimeric. Conclusions/Significance Our observations provide the best evidence gathered so far for the role of TEs in the generation of Drosophila inversions. In addition, they show unequivocally that ectopic recombination is the causative mechanism. The fact that the three polymorphic D. buzzatii inversions investigated so far were generated by the same transposon family is remarkable and is conceivably due to Galileo's unusual structure and current (or recent) transpositional activity.
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Affiliation(s)
- Alejandra Delprat
- Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain
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Gunderina LI, Kiknadze II, Istomina AG, Butler M. Geographic differentiation of genomic DNA of Chironomus plumosus (Diptera, Chironomidae) in natural holarctic populations. RUSS J GENET+ 2009. [DOI: 10.1134/s1022795409010086] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Thermal evolution of gene expression profiles in Drosophila subobscura. BMC Evol Biol 2007; 7:42. [PMID: 17371595 PMCID: PMC1847442 DOI: 10.1186/1471-2148-7-42] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Accepted: 03/19/2007] [Indexed: 11/17/2022] Open
Abstract
Background Despite its pervasiveness, the genetic basis of adaptation resulting in variation directly or indirectly related to temperature (climatic) gradients is poorly understood. By using 3-fold replicated laboratory thermal stocks covering much of the physiologically tolerable temperature range for the temperate (i.e., cold tolerant) species Drosophila subobscura we have assessed whole-genome transcriptional responses after three years of thermal adaptation, when the populations had already diverged for inversion frequencies, pre-adult life history components, and morphological traits. Total mRNA from each population was compared to a reference pool mRNA in a standard, highly replicated two-colour competitive hybridization experiment using cDNA microarrays. Results A total of 306 (6.6%) cDNA clones were identified as 'differentially expressed' (following a false discovery rate correction) after contrasting the two furthest apart thermal selection regimes (i.e., 13°C vs . 22°C), also including four previously reported candidate genes for thermotolerance in Drosophila (Hsp26, Hsp68, Fst, and Treh). On the other hand, correlated patterns of gene expression were similar in cold- and warm-adapted populations. Analysis of functional categories defined by the Gene Ontology project point to an overrepresentation of genes involved in carbohydrate metabolism, nucleic acids metabolism and regulation of transcription among other categories. Although the location of differently expressed genes was approximately at random with respect to chromosomes, a physical mapping of 88 probes to the polytene chromosomes of D. subobscura has shown that a larger than expected number mapped inside inverted chromosomal segments. Conclusion Our data suggest that a sizeable number of genes appear to be involved in thermal adaptation in Drosophila, with a substantial fraction implicated in metabolism. This apparently illustrates the formidable challenge to understanding the adaptive evolution of complex trait variation. Furthermore, some clustering of genes within inverted chromosomal sections was detected. Disentangling the effects of inversions will be obviously required in any future approach if we want to identify the relevant candidate genes.
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Vaulin OV, Gunderina LI, Zakharov IK. Polymorphism and differentiation of multilocus DNA markers in natural populations of Drosophila melanogaster. RUSS J GENET+ 2007. [DOI: 10.1134/s1022795407010085] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Abstract
Insects comprise the largest species composition in the entire animal kingdom and possess a vast undiscovered genetic diversity and gene pool that can be better explored using molecular marker techniques. Current trends of application of DNA marker techniques in diverse domains of insect ecological studies show that mitochondrial DNA (mtDNA), microsatellites, random amplified polymorphic DNA (RAPD), expressed sequence tags (EST) and amplified fragment length polymorphism (AFLP) markers have contributed significantly for progresses towards understanding genetic basis of insect diversity and for mapping medically and agriculturally important genes and quantitative trait loci in insect pests. Apart from these popular marker systems, other novel approaches including transposon display, sequence-specific amplification polymorphism (S-SAP), repeat-associated polymerase chain reaction (PCR) markers have been identified as alternate marker systems in insect studies. Besides, whole genome microarray and single nucleotide polymorphism (SNP) assays are becoming more popular to screen genome-wide polymorphisms in fast and cost effective manner. However, use of such methodologies has not gained widespread popularity in entomological studies. The current study highlights the recent trends of applications of molecular markers in insect studies and explores the technological advancements in molecular marker tools and modern high throughput genotyping methodologies that may be applied in entomological researches for better understanding of insect ecology at molecular level.
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Affiliation(s)
- Susanta K Behura
- Department of Entomology, 505 S Goodwin Avenue, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
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Variation and Divergence of Multilocus Genome Markers in the Species of the Genus Chironomus (Diptera, Chironomidae). RUSS J GENET+ 2005. [DOI: 10.1007/s11177-006-0006-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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González J, Nefedov M, Bosdet I, Casals F, Calvete O, Delprat A, Shin H, Chiu R, Mathewson C, Wye N, Hoskins RA, Schein JE, de Jong P, Ruiz A. A BAC-based physical map of the Drosophila buzzatii genome. Genome Res 2005; 15:885-92. [PMID: 15930498 PMCID: PMC1142479 DOI: 10.1101/gr.3263105] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Accepted: 03/22/2005] [Indexed: 01/03/2023]
Abstract
Large-insert genomic libraries facilitate cloning of large genomic regions, allow the construction of clone-based physical maps, and provide useful resources for sequencing entire genomes. Drosophila buzzatii is a representative species of the repleta group in the Drosophila subgenus, which is being widely used as a model in studies of genome evolution, ecological adaptation, and speciation. We constructed a Bacterial Artificial Chromosome (BAC) genomic library of D. buzzatii using the shuttle vector pTARBAC2.1. The library comprises 18,353 clones with an average insert size of 152 kb and an approximately 18x expected representation of the D. buzzatii euchromatic genome. We screened the entire library with six euchromatic gene probes and estimated the actual genome representation to be approximately 23x. In addition, we fingerprinted by restriction digestion and agarose gel electrophoresis a sample of 9555 clones, and assembled them using FingerPrint Contigs (FPC) software and manual editing into 345 contigs (mean of 26 clones per contig) and 670 singletons. Finally, we anchored 181 large contigs (containing 7788 clones) to the D. buzzatii salivary gland polytene chromosomes by in situ hybridization of 427 representative clones. The BAC library and a database with all the information regarding the high coverage BAC-based physical map described in this paper are available to the research community.
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Affiliation(s)
- Josefa González
- Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain
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Khoo G, Lim MH, Suresh H, Gan DKY, Lim KF, Chen F, Chan WK, Lim TM, Phang VPE. Genetic linkage maps of the guppy ( Poecilia reticulata): assignment of RAPD markers to multipoint linkage groups. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2003; 5:279-293. [PMID: 14502400 DOI: 10.1007/s10126-002-0072-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2002] [Accepted: 08/20/2002] [Indexed: 05/24/2023]
Abstract
Genetic linkage maps of the guppy ( Poecilia reticulata) were constructed from independent crosses between the Tuxedo strain and a feral line (Wildtype). Segregation patterns of random amplified polymorphic DNA (RAPD) markers and phenotypic markers were investigated in F(2) offspring of Tuxedo male symbol male symbol x Wildtype female symbol female symbol and Wildtype male symbol male symbol x Tuxedo female symbol female symbol crosses. Among the 300 and 276 RAPD markers scored for the respective crosses, linkages were identified for 230 and 212, respectively. The Tuxedo male symbol male symbol x Wildtype female symbol female symbol and Wildtype male symbol male symbol x Tuxedo female symbol female symbol maps spanned 2100 Kosambi centiMorgans (cM(K)) and 1900 cM(K), respectively, in 28 linkage groups. Average marker resolution was 10 cM(K). Genome length was estimated at 4410 cM(K) and 4060 cM(K) for the respective crosses, with an average physical distance of 166 kbp/cM(K). Several RAPD markers were closely linked to or mapped onto the loci for the sex-determining region (SdR), and the sex-linked black caudal-peduncle ( Bcp) and red tail ( Rdt) genes. These primary linkage maps are the initial step toward the construction of a composite high-density map to facilitate map-based cloning and marker-assisted selection of quantitative trait loci that are essential for the development of comprehensive breeding programs for the guppy.
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Affiliation(s)
- Gideon Khoo
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Republic of Singapore
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González J, Ranz JM, Ruiz A. Chromosomal elements evolve at different rates in the Drosophila genome. Genetics 2002; 161:1137-54. [PMID: 12136017 PMCID: PMC1462194 DOI: 10.1093/genetics/161.3.1137] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recent results indicate that the rate of chromosomal rearrangement in the genus Drosophila is the highest found so far in any eukaryote. This conclusion is based chiefly on the comparative mapping analysis of a single chromosomal element (Muller's element E) in two species, D. melanogaster and D. repleta, representing the two farthest lineages within the genus (the Sophophora and Drosophila subgenera, respectively). We have extended the analysis to two other chromosomal elements (Muller's elements A and D) and tested for differences in rate of evolution among chromosomes. With this purpose, detailed physical maps of chromosomes X and 4 of D. repleta were constructed by in situ hybridization of 145 DNA probes (gene clones, cosmids, and P1 phages) and their gene arrangements compared with those of the homologous chromosomes X and 3L of D. melanogaster. Both chromosomal elements have been extensively reshuffled over their entire length. The number of paracentric inversions fixed has been estimated as 118 +/- 17 for element A and 56 +/- 8 for element D. Comparison with previous data for elements E and B shows that there are fourfold differences in evolution rate among chromosomal elements, with chromosome X exhibiting the highest rate of rearrangement. Combining all results, we estimated that 393 paracentric inversions have been fixed in the whole genome since the divergence between D. repleta and D. melanogaster. This amounts to an average rate of 0.053 disruptions/Mb/myr, corroborating the high rate of rearrangement in the genus Drosophila.
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Affiliation(s)
- Josefa González
- Departament de Genètica i de Microbiologia, Facultat de Ciències-Edifici C, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain
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