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Manrique-Poyato MI, Cabrero J, López-León MD, Perfectti F, Gómez R, Camacho JPM. Interpopulation spread of a parasitic B chromosome is unlikely through males in the grasshopper Eyprepocnemis plorans. Heredity (Edinb) 2019; 124:197-206. [PMID: 31285567 DOI: 10.1038/s41437-019-0248-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 06/11/2019] [Accepted: 06/25/2019] [Indexed: 11/09/2022] Open
Abstract
The near-neutral model of B chromosome evolution predicts that population invasion is quite fast. To test this prediction, in 1994, we introduced males of the grasshopper Eyprepocnemis plorans from a B-carrying population into a B-lacking population and monitored the evolution of B-chromosome frequency up to 2013. We observed fluctuating very low B frequency across years but, remarkably, the B chromosome introduced (the B2 variant) was found up to 1996 only, whereas the B1 variant was present from 1996 onwards, presumably introduced by fishermen using E. plorans males as bait. Effective introgression of genetic material from the donor population was evidenced by the presence of a satellite DNA on autosome 9 (up to 1999) and the presence of one individual in 2006 showing an ISSR marker profile being highly similar to that found in the donor population. This indicated that the males introduced by us effectively mated with resident females, but donor genes rapidly decreased in frequency after this non-recurrent migration event. Taken together, our results indicated: (i) that the non-recurrent migration event had a slight, transient genetic effect on the recipient population, which was diluted in only a few generations; and (ii) that even with recurrent migration (forced by fishermen) the B chromosome failed to increase in frequency. Bearing in mind that B chromosomes in this species drive through females only, we hypothesize that B chromosomes most likely failed invasion in both migration events because the migrating sex shows no B-drive.
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Affiliation(s)
| | - Josefa Cabrero
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, 18071, Granada, Spain
| | - María Dolores López-León
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, 18071, Granada, Spain
| | - Francisco Perfectti
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, 18071, Granada, Spain
| | - Ricardo Gómez
- Departamento de Ciencia y Tecnología Agroforestal, E.T.S. de Ingenieros Agrónomos, Universidad de Castilla La Mancha, 02071, Albacete, Spain
| | - Juan Pedro M Camacho
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, 18071, Granada, Spain.
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Hanlon SL, Miller DE, Eche S, Hawley RS. Origin, Composition, and Structure of the Supernumerary B Chromosome of Drosophila melanogaster. Genetics 2018; 210:1197-1212. [PMID: 30249684 PMCID: PMC6283169 DOI: 10.1534/genetics.118.301478] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 09/23/2018] [Indexed: 01/18/2023] Open
Abstract
The number of chromosomes carried by an individual species is one of its defining characteristics. Some species, however, can also carry supernumerary chromosomes referred to as B chromosomes. B chromosomes were recently identified in a laboratory stock of Drosophila melanogaster-an established model organism with a wealth of genetic and genomic resources-enabling us to subject them to extensive molecular analysis. We isolated the B chromosomes by pulsed-field gel electrophoresis and determined their composition through next-generation sequencing. Although these B chromosomes carry no known euchromatic sequence, they are rich in transposable elements and long arrays of short nucleotide repeats, the most abundant being the uncharacterized AAGAT satellite repeat. Fluorescent in situ hybridization on metaphase chromosome spreads revealed this repeat is located on chromosome 4, strongly suggesting the origin of the B chromosomes is chromosome 4 Cytological and quantitative comparisons of signal intensity between chromosome 4 and the B chromosomes supports the hypothesis that the structure of the B chromosome is an isochromosome. We also report the identification of a new B chromosome variant in a related laboratory stock. This B chromosome has a similar repeat signature as the original but is smaller and much less prevalent. We examined additional stocks with similar genotypes and did not find B chromosomes, but did find these stocks lacked the AAGAT satellite repeat. Our molecular characterization of D. melanogaster B chromosomes is the first step toward understanding how supernumerary chromosomes arise from essential chromosomes and what may be necessary for their stable inheritance.
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Affiliation(s)
- Stacey L Hanlon
- Stowers Institute for Medical Research, Kansas City, Missouri 64110
| | - Danny E Miller
- Department of Pediatrics, Seattle Children's Hospital, University of Washington, Seattle, Washington 98105
| | - Salam Eche
- Stowers Institute for Medical Research, Kansas City, Missouri 64110
| | - R Scott Hawley
- Stowers Institute for Medical Research, Kansas City, Missouri 64110
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas 66160
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