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Post-meiotic B chromosome expulsion, during spermiogenesis, in two grasshopper species.
Chromosoma. 2017 Oct; 126(5):633-644.C

Abstract

Most supernumerary (B) chromosomes are parasitic elements carrying out an evolutionary arms race with the standard (A) chromosomes. A variety of weapons for attack and defense have evolved in both contending elements, the most conspicuous being B chromosome drive and A chromosome drive suppression. Here, we show for the first time that most microspermatids formed during spermiogenesis in two grasshopper species contain expulsed B chromosomes. By using DNA probes for B-specific satellite DNAs in Eumigus monticola and Eyprepocnemis plorans, and also 18S rDNA in the latter species, we were able to count the number of B chromosomes in standard spermatids submitted to fluorescence in situ hybridization, as well as visualizing B chromosomes inside most microspermatids. In E. plorans, the presence of B-carrying microspermatids in 1B males was associated with a significant decrease in the proportion of B-carrying standard spermatids. The fact that this decrease was apparent in elongating spermatids but not in round ones demonstrates that meiosis yields 1:1 proportions of 0B and 1B spermatids and hence that B elimination takes place post-meiotically, i.e., during spermiogenesis, implying a 5-25% decrease in B transmission rate. In E. monticola, the B chromosome is mitotically unstable and B number varies between cells within a same individual. A comparison of B frequency between round and elongating spermatids of a same individual revealed a significant 12.3% decrease. We conclude that B chromosome elimination during spermiogenesis is a defense weapon of the host genome to get rid of parasitic chromosomes.

Authors+Show Affiliations

Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, Granada, Spain.Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, Granada, Spain.Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, Granada, Spain.Departamento de Ciencia y Tecnología Agroforestal, E.T.S. de Ingenieros Agrónomos, Universidad de Castilla La Mancha, 02071, Albacete, Spain.Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, Granada, Spain. jpmcamac@ugr.es.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

28190081

Citation

Cabrero, Josefa, et al. "Post-meiotic B Chromosome Expulsion, During Spermiogenesis, in Two Grasshopper Species." Chromosoma, vol. 126, no. 5, 2017, pp. 633-644.
Cabrero J, Martín-Peciña M, Ruiz-Ruano FJ, et al. Post-meiotic B chromosome expulsion, during spermiogenesis, in two grasshopper species. Chromosoma. 2017;126(5):633-644.
Cabrero, J., Martín-Peciña, M., Ruiz-Ruano, F. J., Gómez, R., & Camacho, J. P. M. (2017). Post-meiotic B chromosome expulsion, during spermiogenesis, in two grasshopper species. Chromosoma, 126(5), 633-644. https://doi.org/10.1007/s00412-017-0627-8
Cabrero J, et al. Post-meiotic B Chromosome Expulsion, During Spermiogenesis, in Two Grasshopper Species. Chromosoma. 2017;126(5):633-644. PubMed PMID: 28190081.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Post-meiotic B chromosome expulsion, during spermiogenesis, in two grasshopper species. AU - Cabrero,Josefa, AU - Martín-Peciña,María, AU - Ruiz-Ruano,Francisco J, AU - Gómez,Ricardo, AU - Camacho,Juan Pedro M, Y1 - 2017/02/11/ PY - 2016/12/14/received PY - 2017/01/31/accepted PY - 2017/01/29/revised PY - 2017/2/13/pubmed PY - 2018/7/24/medline PY - 2017/2/13/entrez KW - FISH KW - Micronucleus KW - Microspermatids KW - Parasitic KW - Satellite DNA SP - 633 EP - 644 JF - Chromosoma JO - Chromosoma VL - 126 IS - 5 N2 - Most supernumerary (B) chromosomes are parasitic elements carrying out an evolutionary arms race with the standard (A) chromosomes. A variety of weapons for attack and defense have evolved in both contending elements, the most conspicuous being B chromosome drive and A chromosome drive suppression. Here, we show for the first time that most microspermatids formed during spermiogenesis in two grasshopper species contain expulsed B chromosomes. By using DNA probes for B-specific satellite DNAs in Eumigus monticola and Eyprepocnemis plorans, and also 18S rDNA in the latter species, we were able to count the number of B chromosomes in standard spermatids submitted to fluorescence in situ hybridization, as well as visualizing B chromosomes inside most microspermatids. In E. plorans, the presence of B-carrying microspermatids in 1B males was associated with a significant decrease in the proportion of B-carrying standard spermatids. The fact that this decrease was apparent in elongating spermatids but not in round ones demonstrates that meiosis yields 1:1 proportions of 0B and 1B spermatids and hence that B elimination takes place post-meiotically, i.e., during spermiogenesis, implying a 5-25% decrease in B transmission rate. In E. monticola, the B chromosome is mitotically unstable and B number varies between cells within a same individual. A comparison of B frequency between round and elongating spermatids of a same individual revealed a significant 12.3% decrease. We conclude that B chromosome elimination during spermiogenesis is a defense weapon of the host genome to get rid of parasitic chromosomes. SN - 1432-0886 UR - https://www.unboundmedicine.com/medline/citation/28190081/Post_meiotic_B_chromosome_expulsion_during_spermiogenesis_in_two_grasshopper_species_ L2 - https://dx.doi.org/10.1007/s00412-017-0627-8 DB - PRIME DP - Unbound Medicine ER -