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Marshall H, de la Filia AG, Cavalieri R, Mallon EB, Clark JM, Ross L. Lack of paternal silencing and ecotype-specific expression in head and body lice hybrids. Evol Lett 2024; 8:455-465. [PMID: 38818422 PMCID: PMC11134467 DOI: 10.1093/evlett/qrae003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 12/27/2023] [Accepted: 01/22/2024] [Indexed: 06/01/2024] Open
Abstract
Paternal genome elimination (PGE) is a non-Mendelian inheritance system, described in numerous arthropod species, in which males develop from fertilized eggs, but their paternally inherited chromosomes are eliminated before or during spermatogenesis. Therefore, PGE males only transmit their maternally inherited set of chromosomes to their offspring. In addition to the elimination of paternal chromosomes, diverse PGE species have also repeatedly evolved the transcriptional silencing of the paternal genome, making males effectively haploid. However, it is unclear if this paternal chromosome silencing is mechanistically linked to the chromosome elimination or has evolved at a later stage, and if so, what drives the haploidization of males under PGE. In order to understand these questions, here we study the human louse, Pediculus humanus, which represents an ideal model system, as it appears to be the only instance of PGE where males eliminate, but not silence their paternal chromosomes, although the latter remains to be shown conclusively. In this study, we analyzed parent-of-origin allele-specific expression patterns in male offspring of crosses between head and body lice ecotypes. We show that hybrid adult males of P. humanus display biparental gene expression, which constitutes the first case of a species with PGE in which genetic activity of paternal chromosomes in the soma is not affected by embryonic silencing or (partial or complete) elimination. We did however also identify a small number of maternally biased genes (potentially imprinted genes), which may be involved in the elimination of paternal chromosomes during spermatogenesis. Finally, we have identified genes that show ecotype-specific expression bias. Given the low genetic diversity between ecotypes, this is suggestive for a role of epigenetic processes in ecotype differences.
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Affiliation(s)
- Hollie Marshall
- School of Biological Sciences, Institute of Evolutionary Biology, The University of Edinburgh, Edinburgh, United Kingdom
- The Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | - Andrés G de la Filia
- School of Biological Sciences, Institute of Evolutionary Biology, The University of Edinburgh, Edinburgh, United Kingdom
| | - Ross Cavalieri
- Massachusetts Pesticide Analysis Lab, Veterinary and Animal Sciences, University of Massachusetts Amherst, Massachusetts, United States
| | - Eamonn B Mallon
- The Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | - John M Clark
- Massachusetts Pesticide Analysis Lab, Veterinary and Animal Sciences, University of Massachusetts Amherst, Massachusetts, United States
| | - Laura Ross
- School of Biological Sciences, Institute of Evolutionary Biology, The University of Edinburgh, Edinburgh, United Kingdom
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Herbette M, Ross L. Paternal genome elimination: patterns and mechanisms of drive and silencing. Curr Opin Genet Dev 2023; 81:102065. [PMID: 37413739 DOI: 10.1016/j.gde.2023.102065] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/24/2023] [Accepted: 05/24/2023] [Indexed: 07/08/2023]
Abstract
In thousands of arthropod species, males inherit, but subsequently eliminate the entire haploid genome of their father. However, why this peculiar reproductive strategy evolved repeatedly across diverse species and what mechanisms are involved in paternal genome elimination (PGE) remains largely unknown. In this review, we summarize what we know about the patterns of paternal chromosome elimination during various stages of development in the diverse taxa that have been studied. We also discuss some other unusual features often associated with PGE, such as the transcriptional silencing of paternally derived chromosomes in males and sex determination through the early embryonic elimination of X chromosomes. Little is known about the molecular mechanisms underlying the parent-of-origin-dependent chromosome elimination and silencing under PGE, but we discuss the insight of several studies that are pioneering this work and highlight directions for future research.
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Affiliation(s)
- Marion Herbette
- School of Biological Sciences, Institute of Evolutionary Biology, The University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Laura Ross
- School of Biological Sciences, Institute of Evolutionary Biology, The University of Edinburgh, Edinburgh EH9 3FL, UK.
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Kuznetsova VG, Gavrilov-Zimin IA, Grozeva SM, Golub NV. Comparative analysis of chromosome numbers and sex chromosome systems in Paraneoptera (Insecta). COMPARATIVE CYTOGENETICS 2021; 15:279-327. [PMID: 34616525 PMCID: PMC8490342 DOI: 10.3897/compcytogen.v15.i3.71866] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 09/06/2021] [Indexed: 05/28/2023]
Abstract
This article is part (the 4th article) of the themed issue (a monograph) "Aberrant cytogenetic and reproductive patterns in the evolution of Paraneoptera". The purpose of this article is to consider chromosome structure and evolution, chromosome numbers and sex chromosome systems, which all together constitute the chromosomal basis of reproduction and are essential for reproductive success. We are based on our own observations and literature data available for all major lineages of Paraneoptera including Zoraptera (angel insects), Copeognatha (=Psocoptera; bark lice), Parasita (=Phthiraptera s. str; true lice), Thysanoptera (thrips), Homoptera (scale insects, aphids, jumping plant-lice, whiteflies, and true hoppers), Heteroptera (true bugs), and Coleorrhyncha (moss bugs). Terminology, nomenclature, classification, and the study methods are given in the first paper of the issue (Gavrilov-Zimin et al. 2021).
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Affiliation(s)
- Valentina G. Kuznetsova
- Zoological Institute, Russian Academy of Sciences, Universitetskaya emb. 1, St. Petersburg, 199034, RussiaZoological Institute, Russian Academy of SciencesSt. PetersburgRussia
| | - Ilya A. Gavrilov-Zimin
- Zoological Institute, Russian Academy of Sciences, Universitetskaya emb. 1, St. Petersburg, 199034, RussiaZoological Institute, Russian Academy of SciencesSt. PetersburgRussia
| | - Snejana M. Grozeva
- Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Blvd Tsar Osvoboditel 1, Sofia 1000, BulgariaInstitute of Biodiversity and Ecosystem Research, Bulgarian Academy of SciencesSofiaBulgaria
| | - Natalia V. Golub
- Zoological Institute, Russian Academy of Sciences, Universitetskaya emb. 1, St. Petersburg, 199034, RussiaZoological Institute, Russian Academy of SciencesSt. PetersburgRussia
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DE LA FILIA AG, ANDREWES S, CLARK JM, ROSS L. The unusual reproductive system of head and body lice (Pediculus humanus). MEDICAL AND VETERINARY ENTOMOLOGY 2018; 32:226-234. [PMID: 29266297 PMCID: PMC5947629 DOI: 10.1111/mve.12287] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 09/07/2017] [Accepted: 11/02/2017] [Indexed: 05/08/2023]
Abstract
Insect reproduction is extremely variable, but the implications of alternative genetic systems are often overlooked in studies on the evolution of insecticide resistance. Both ecotypes of Pediculus humanus (Phthiraptera: Pediculidae), the human head and body lice, are human ectoparasites, the control of which is challenged by the recent spread of resistance alleles. The present study conclusively establishes for the first time that both head and body lice reproduce through paternal genome elimination (PGE), an unusual genetic system in which males transmit only their maternally derived chromosomes. Here, we investigate inheritance patterns of parental genomes using a genotyping approach across families of both ecotypes and show that heterozygous males exclusively or preferentially pass on one allele only, whereas females transmit both in a Mendelian fashion. We do however observe occasional transmission of paternal chromosomes through males, representing the first known case of PGE in which whole-genome meiotic drive is incomplete. Finally, we discuss the potential implications of this finding for the evolution of resistance and invite the development of new theoretical models of how this knowledge might contribute to increasing the success of pediculicide-based management schemes.
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Affiliation(s)
- A. G. DE LA FILIA
- School of Biological Sciences, Institute of Evolutionary BiologyUniversity of EdinburghEdinburghU.K.
| | - S. ANDREWES
- Departnent of Veterinary and Animal SciencesUniversity of Massachusetts AmherstAmherstMAU.S.A.
| | - J. M. CLARK
- Departnent of Veterinary and Animal SciencesUniversity of Massachusetts AmherstAmherstMAU.S.A.
| | - L. ROSS
- School of Biological Sciences, Institute of Evolutionary BiologyUniversity of EdinburghEdinburghU.K.
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Hodson CN, Hamilton PT, Dilworth D, Nelson CJ, Curtis CI, Perlman SJ. Paternal Genome Elimination in Liposcelis Booklice (Insecta: Psocodea). Genetics 2017; 206:1091-1100. [PMID: 28292917 PMCID: PMC5499165 DOI: 10.1534/genetics.117.199786] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 03/07/2017] [Indexed: 11/18/2022] Open
Abstract
How sex is determined in insects is diverse and dynamic, and includes male heterogamety, female heterogamety, and haplodiploidy. In many insect lineages, sex determination is either completely unknown or poorly studied. We studied sex determination in Psocodea-a species-rich order of insects that includes parasitic lice, barklice, and booklice. We focus on a recently discovered species of Liposcelis booklice (Psocodea: Troctomorpha), which are among the closest free-living relatives of parasitic lice. Using genetic, genomic, and immunohistochemical approaches, we show that this group exhibits paternal genome elimination (PGE), an unusual mode of sex determination that involves genomic imprinting. Controlled crosses, following a genetic marker over multiple generations, demonstrated that males only transmit to offspring genes they inherited from their mother. Immunofluorescence microscopy revealed densely packed chromocenters associated with H3K9me3-a conserved marker for heterochromatin-in males, but not in females, suggesting silencing of chromosomes in males. Genome assembly and comparison of read coverage in male and female libraries showed no evidence for differentiated sex chromosomes. We also found that females produce more sons early in life, consistent with facultative sex allocation. It is likely that PGE is widespread in Psocodea, including human lice. This order represents a promising model for studying this enigmatic mode of sex determination.
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Affiliation(s)
- Christina N Hodson
- Department of Biology, University of Victoria, V8P 5C2, Canada
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, EH9 3JG, United Kingdom
| | | | - Dave Dilworth
- Department of Biochemistry and Microbiology, University of Victoria, V8P 5C2, Canada
| | - Chris J Nelson
- Department of Biochemistry and Microbiology, University of Victoria, V8P 5C2, Canada
| | | | - Steve J Perlman
- Department of Biology, University of Victoria, V8P 5C2, Canada
- Integrated Microbial Biodiversity Program, Canadian Institute for Advanced Research, Toronto M5G 1Z8, Canada
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Blackmon H, Ross L, Bachtrog D. Sex Determination, Sex Chromosomes, and Karyotype Evolution in Insects. J Hered 2017; 108:78-93. [PMID: 27543823 PMCID: PMC6281344 DOI: 10.1093/jhered/esw047] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 07/25/2016] [Indexed: 01/02/2023] Open
Abstract
Insects harbor a tremendous diversity of sex determining mechanisms both within and between groups. For example, in some orders such as Hymenoptera, all members are haplodiploid, whereas Diptera contain species with homomorphic as well as male and female heterogametic sex chromosome systems or paternal genome elimination. We have established a large database on karyotypes and sex chromosomes in insects, containing information on over 13000 species covering 29 orders of insects. This database constitutes a unique starting point to report phylogenetic patterns on the distribution of sex determination mechanisms, sex chromosomes, and karyotypes among insects and allows us to test general theories on the evolutionary dynamics of karyotypes, sex chromosomes, and sex determination systems in a comparative framework. Phylogenetic analysis reveals that male heterogamety is the ancestral mode of sex determination in insects, and transitions to female heterogamety are extremely rare. Many insect orders harbor species with complex sex chromosomes, and gains and losses of the sex-limited chromosome are frequent in some groups. Haplodiploidy originated several times within insects, and parthenogenesis is rare but evolves frequently. Providing a single source to electronically access data previously distributed among more than 500 articles and books will not only accelerate analyses of the assembled data, but also provide a unique resource to guide research on which taxa are likely to be informative to address specific questions, for example, for genome sequencing projects or large-scale comparative studies.
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Affiliation(s)
- Heath Blackmon
- From the Department of Ecology, Evolution, and Behavior, University of Minnesota, Minneapolis, MN (Blackmon); Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK (Ross); Department of Integrative Biology, University of California Berkeley, Berkeley, CA (Bachtrog)
| | - Laura Ross
- From the Department of Ecology, Evolution, and Behavior, University of Minnesota, Minneapolis, MN (Blackmon); Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK (Ross); Department of Integrative Biology, University of California Berkeley, Berkeley, CA (Bachtrog)
| | - Doris Bachtrog
- From the Department of Ecology, Evolution, and Behavior, University of Minnesota, Minneapolis, MN (Blackmon); Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK (Ross); Department of Integrative Biology, University of California Berkeley, Berkeley, CA (Bachtrog).
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Bressa MJ, Papeschi AG, Toloza AC. Cytogenetic Features of Human Head and Body Lice (Phthiraptera: Pediculidae). JOURNAL OF MEDICAL ENTOMOLOGY 2015; 52:918-24. [PMID: 26336229 DOI: 10.1093/jme/tjv089] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 06/09/2015] [Indexed: 05/08/2023]
Abstract
The genus Pediculus L. that parasitize humans comprise two subspecies: the head lice Pediculus humanus capitis De Geer and the body lice Pediculus humanus humanus De Geer. Despite the 200 yr of the first description of these two species, there is still a long debate about their taxonomic status. Some authors proposed that these organisms are separate species, conspecifics, or grouped in clades. The sequencing of both forms indicated that the difference between them is one gene absent in the head louse. However, their chromosomal number remains to be determined. In this study, we described the male and female karyotypes, and male meiosis of head and body lice, and examined the chromatin structure by means of C-banding. In P. h. humanus and P. h. capitis, the diploid chromosome complement was 2 n = 12 in both sexes. In oogonial prometaphase and metaphase and spermatogonial metaphase, it is evident that chromosomes lack of a primary constriction. No identifiable sex chromosomes or B chromosomes were observed in head and body lice. Neither chiasmata nor chromatin connections between homologous chromosomes were detected in male meiosis. The meiotic behaviour of the chromosomes showed that they are holokinetic. C-banding revealed the absence of constitutive heterochromatin. Our results provide relevant information to be used in mapping studies of genes associated with sex determination and environmental sensing and response.
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Affiliation(s)
- María José Bressa
- Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
| | - Alba Graciela Papeschi
- Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Ariel Ceferino Toloza
- Centro de Investigaciones de Plagas e Insecticidas (UNIDEF/CONICET), Juan Bautista de La Salle 4397, Villa Martelli, Buenos Aires, Argentina
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Drinnenberg IA, deYoung D, Henikoff S, Malik HS. Recurrent loss of CenH3 is associated with independent transitions to holocentricity in insects. eLife 2014; 3. [PMID: 25247700 DOI: 10.7554/elife.03676.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 08/25/2014] [Indexed: 05/24/2023] Open
Abstract
Faithful chromosome segregation in all eukaryotes relies on centromeres, the chromosomal sites that recruit kinetochore proteins and mediate spindle attachment during cell division. The centromeric histone H3 variant, CenH3, is the defining chromatin component of centromeres in most eukaryotes, including animals, fungi, plants, and protists. In this study, using detailed genomic and transcriptome analyses, we show that CenH3 was lost independently in at least four lineages of insects. Each of these lineages represents an independent transition from monocentricity (centromeric determinants localized to a single chromosomal region) to holocentricity (centromeric determinants extended over the entire chromosomal length) as ancient as 300 million years ago. Holocentric insects therefore contain a CenH3-independent centromere, different from almost all the other eukaryotes. We propose that ancient transitions to holocentricity in insects obviated the need to maintain CenH3, which is otherwise essential in most eukaryotes, including other holocentrics.
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Affiliation(s)
- Ines A Drinnenberg
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Dakota deYoung
- Department of Biology, University of Washington, Seattle, United States
| | - Steven Henikoff
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Harmit Singh Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
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Drinnenberg IA, deYoung D, Henikoff S, Malik HS. Recurrent loss of CenH3 is associated with independent transitions to holocentricity in insects. eLife 2014; 3:e03676. [PMID: 25247700 PMCID: PMC4359364 DOI: 10.7554/elife.03676] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 08/25/2014] [Indexed: 01/15/2023] Open
Abstract
Faithful chromosome segregation in all eukaryotes relies on centromeres, the chromosomal sites that recruit kinetochore proteins and mediate spindle attachment during cell division. The centromeric histone H3 variant, CenH3, is the defining chromatin component of centromeres in most eukaryotes, including animals, fungi, plants, and protists. In this study, using detailed genomic and transcriptome analyses, we show that CenH3 was lost independently in at least four lineages of insects. Each of these lineages represents an independent transition from monocentricity (centromeric determinants localized to a single chromosomal region) to holocentricity (centromeric determinants extended over the entire chromosomal length) as ancient as 300 million years ago. Holocentric insects therefore contain a CenH3-independent centromere, different from almost all the other eukaryotes. We propose that ancient transitions to holocentricity in insects obviated the need to maintain CenH3, which is otherwise essential in most eukaryotes, including other holocentrics.
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Affiliation(s)
- Ines A Drinnenberg
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Dakota deYoung
- Department of Biology, University of Washington, Seattle, United States
| | - Steven Henikoff
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Harmit Singh Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, United States
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Pittendrigh BR, Clark JM, Johnston JS, Lee SH, Romero-Severson J, Dasch GA. Sequencing of a new target genome: the Pediculus humanus humanus (Phthiraptera: Pediculidae) genome project. JOURNAL OF MEDICAL ENTOMOLOGY 2006; 43:1103-11. [PMID: 17162941 DOI: 10.1603/0022-2585(2006)43[1103:soantg]2.0.co;2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The human body louse, Pediculus humanus humanus (L.), and the human head louse, Pediculus humanus capitis, belong to the hemimetabolous order Phthiraptera. The body louse is the primary vector that transmits the bacterial agents of louse-borne relapsing fever, trench fever, and epidemic typhus. The genomes of the bacterial causative agents of several of these aforementioned diseases have been sequenced. Thus, determining the body louse genome will enhance studies of host-vector-pathogen interactions. Although not important as a major disease vector, head lice are of major social concern. Resistance to traditional pesticides used to control head and body lice have developed. It is imperative that new molecular targets be discovered for the development of novel compounds to control these insects. No complete genome sequence exists for a hemimetabolous insect species primarily because hemimetabolous insects often have large (2000 Mb) to very large (up to 16,300 Mb) genomes. Fortuitously, we determined that the human body louse has one of the smallest genome sizes known in insects, suggesting it may be a suitable choice as a minimal hemimetabolous genome in which many genes have been eliminated during its adaptation to human parasitism. Because many louse species infest birds and mammals, the body louse genome-sequencing project will facilitate studies of their comparative genomics. A 6-8X coverage of the body louse genome, plus sequenced expressed sequence tags, should provide the entomological, evolutionary biology, medical, and public health communities with useful genetic information.
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Affiliation(s)
- B R Pittendrigh
- Department of Entomology, Purdue University, West Lafayette, IN 47907, USA.
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McMeniman CJ, Barker SC. Transmission ratio distortion in the human body louse, Pediculus humanus (Insecta: Phthiraptera). Heredity (Edinb) 2006; 96:63-8. [PMID: 16175192 DOI: 10.1038/sj.hdy.6800760] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We studied inheritance at three microsatellite loci in eight F, and two F2 families of the body (clothes) louse of humans, Pediculus humanus. The alleles of heterozygous female-parents were always inherited in a Mendelian fashion in these families. Alleles from heterozygous male-parents, however, were inherited in two different ways: (i) in a Mendelian fashion and (ii) in a non-Mendelian fashion, where males passed to their offspring only one of their two alleles, that is, 100% nonrandom transmission. In male body lice, where there was non-Mendelian inheritance, the paternally inherited set of alleles was eliminated. We interpret this pattern of inheritance as evidence for extreme transmission ratio distortion of paternal alleles in this species.
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Affiliation(s)
- C J McMeniman
- Parasitology Section, School of Molecular and Microbial Sciences, University of Queensland, Brisbane 4072, Australia.
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Kuznetsova VG, Nokkala S, Shcherbakov DE. Karyotype, reproductive organs, and pattern of gametogenesis in Zorotypus hubbardi Caudell (Insecta: Zoraptera, Zorotypidae), with discussion on relationships of the order. CAN J ZOOL 2002. [DOI: 10.1139/z02-074] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
For the first time, the karyotype is described in a representative of the order Zoraptera. Zorotypus hubbardi Caudell (Zorotypidae) have holokinetic chromosomes and male karotype of 2n = 38 (36 + neo-XY). Males possess two follicles in each testis and females have six panoistic ovarioles in each ovary. Oogenesis and, more closely, spermato genesis, including meiosis and sperm formation, have been studied. Based on the presence of panoistic ovaries and holokinetic chromosomes, Crampton's hypothesis that Zoraptera represent a group of Polyneoptera nearest to the origin of Paraneoptera is considered the most plausible.
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Maryanska-Nadachowska A, Kuznetsova VG, Taylor GS. Meiotic karyotypes and structure of testes in males of 12 species of Psyllidae: Acizziinae, Carsidaridae and Triozidae (Hemiptera: Psylloidea) from Australia. ACTA ACUST UNITED AC 2001. [DOI: 10.1046/j.1440-6055.2001.00231.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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