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Breed WG, Leigh CM, Peirce EJ. The highly divergent spermatozoon of the Palawan spiny rat, Maxomys panglima has an extremely long tail. Reprod Fertil Dev 2022; 34:526-530. [PMID: 35201976 DOI: 10.1071/rd21255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/28/2021] [Indexed: 11/23/2022] Open
Abstract
CONTEXT Sperm morphology varies greatly across mammalian species and this variability is especially evident in murid rodents with both sperm head shape and tail length being sexually selected traits. The Palawan spiny rat, Maxomys panglima has a longer sperm tail than that currently recorded for any other mammalian species. AIMS The aim of the current study was to determine the sperm morphology of an individual Palawan spiny rat, M. panglima . METHODS Light and transmission electron microscopy were carried out. KEY RESULTS We found that the sperm tail of M. panglima has an average length of 380μm with the midpiece being approximately 185μm in length with comparatively small mitochondria but very large coarse fibres. Furthermore, the sperm head has a less acutely flexed apical hook than that of most other murid rodents including those of several other Maxomys species. CONCLUSIONS The Palawan spiny rat has a highly divergent sperm morphology with an extremely long tail. It may turn out to be an important species for testing various hypotheses of sperm form and function in mammals. IMPLICATIONS These findings suggest markedly different selective pressures may have resulted in this unique sperm morphology, the functional significance of which remains to be determined.
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Affiliation(s)
- W G Breed
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - C M Leigh
- Adelaide Microscopy, University of Adelaide, Adelaide, SA 5005, Australia
| | - E J Peirce
- School of Biomedicine, University of Adelaide, Adelaide, SA 5005, Australia
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2
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Kopania EEK, Larson EL, Callahan C, Keeble S, Good JM. Molecular Evolution across Mouse Spermatogenesis. Mol Biol Evol 2022; 39:6517785. [PMID: 35099536 PMCID: PMC8844503 DOI: 10.1093/molbev/msac023] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Genes involved in spermatogenesis tend to evolve rapidly, but we lack a clear understanding of how protein sequences and patterns of gene expression evolve across this complex developmental process. We used fluorescence-activated cell sorting (FACS) to generate expression data for early (meiotic) and late (postmeiotic) cell types across 13 inbred strains of mice (Mus) spanning ∼7 My of evolution. We used these comparative developmental data to investigate the evolution of lineage-specific expression, protein-coding sequences, and expression levels. We found increased lineage specificity and more rapid protein-coding and expression divergence during late spermatogenesis, suggesting that signatures of rapid testis molecular evolution are punctuated across sperm development. Despite strong overall developmental parallels in these components of molecular evolution, protein and expression divergences were only weakly correlated across genes. We detected more rapid protein evolution on the X chromosome relative to the autosomes, whereas X-linked gene expression tended to be relatively more conserved likely reflecting chromosome-specific regulatory constraints. Using allele-specific FACS expression data from crosses between four strains, we found that the relative contributions of different regulatory mechanisms also differed between cell types. Genes showing cis-regulatory changes were more common late in spermatogenesis, and tended to be associated with larger differences in expression levels and greater expression divergence between species. In contrast, genes with trans-acting changes were more common early and tended to be more conserved across species. Our findings advance understanding of gene evolution across spermatogenesis and underscore the fundamental importance of developmental context in molecular evolutionary studies.
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Affiliation(s)
- Emily E K Kopania
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Erica L Larson
- Department of Biological Sciences, University of Denver, Denver, CO, 80208, USA
| | - Colin Callahan
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Sara Keeble
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Jeffrey M Good
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
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Peirce E, Moya-Smith T, Leigh C, Breed W. Intraspecific variation in testis organisation and sperm head morphology of the delicate mouse (Pseudomys delicatulus): its possible causes and consequences. AUSTRALIAN MAMMALOGY 2022. [DOI: 10.1071/am20057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The delicate mouse (Pseudomys delicatulus) ranges from Queensland to northern Western Australia. In this study the morphology of the cellular organisation of the testis and cauda epididymal spermatozoa are compared. Individuals from the mainland of the Northern Territory and Western Australia invariably have only 60–70% of the testes composed of seminiferous tubules with the interstitial tissue between the tubules containing abundant lipid rich Leydig cells, whereas the cauda epididymal sperm have highly polymorphic, often pear-shaped, heads and basally attached tails. In individuals from Queensland the seminiferous tubules make up approximately 80% of the testis, whereas in the cauda epididymides the sperm populations are generally less variable and have bilaterally flattened heads with the tail attached to the lower concave surface. These differences in the morphology of the delicate mouse testis and spermatozoa in these two geographic regions suggest differences in intensity of intermale sperm competition, with individuals from northern Western Australia and the mainland of the Northern Territory exhibiting monogamy whereas those from Queensland may exhibit some degree of intermale sperm competition and hence possibly have a polyandrous or promiscuous mating system. These findings support the suggestion that P. delicatulus, as currently recognised, contains at least one cryptic species.
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Roycroft E, Achmadi A, Callahan CM, Esselstyn JA, Good JM, Moussalli A, Rowe KC. Molecular Evolution of Ecological Specialisation: Genomic Insights from the Diversification of Murine Rodents. Genome Biol Evol 2021; 13:6275684. [PMID: 33988699 PMCID: PMC8258016 DOI: 10.1093/gbe/evab103] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2021] [Indexed: 12/15/2022] Open
Abstract
Adaptive radiations are characterized by the diversification and ecological differentiation of species, and replicated cases of this process provide natural experiments for understanding the repeatability and pace of molecular evolution. During adaptive radiation, genes related to ecological specialization may be subject to recurrent positive directional selection. However, it is not clear to what extent patterns of lineage-specific ecological specialization (including phenotypic convergence) are correlated with shared signatures of molecular evolution. To test this, we sequenced whole exomes from a phylogenetically dispersed sample of 38 murine rodent species, a group characterized by multiple, nested adaptive radiations comprising extensive ecological and phenotypic diversity. We found that genes associated with immunity, reproduction, diet, digestion, and taste have been subject to pervasive positive selection during the diversification of murine rodents. We also found a significant correlation between genome-wide positive selection and dietary specialization, with a higher proportion of positively selected codon sites in derived dietary forms (i.e., carnivores and herbivores) than in ancestral forms (i.e., omnivores). Despite striking convergent evolution of skull morphology and dentition in two distantly related worm-eating specialists, we did not detect more genes with shared signatures of positive or relaxed selection than in a nonconvergent species comparison. Although a small number of the genes we detected can be incidentally linked to craniofacial morphology or diet, protein-coding regions are unlikely to be the primary genetic basis of this complex convergent phenotype. Our results suggest a link between positive selection and derived ecological phenotypes, and highlight specific genes and general functional categories that may have played an integral role in the extensive and rapid diversification of murine rodents.
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Affiliation(s)
- Emily Roycroft
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia.,Sciences Department, Museums Victoria, Melbourne, Victoria, Australia.,Division of Ecology and Evolution, Research School of Biology, The Australian National University, Acton, Australian Capital Territory, Australia
| | - Anang Achmadi
- Museum Zoologicum Bogoriense, Research Center for Biology, Cibinong, Jawa Barat, Indonesia
| | - Colin M Callahan
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Jacob A Esselstyn
- Museum of Natural Science, Louisiana State University, Baton Rouge, Louisiana, USA.,Department of Biological Sciences, Louisiana State University, Baton Rouge, Los Angeles, USA
| | - Jeffrey M Good
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA.,Wildlife Biology Program, University of Montana, Missoula, Montana, USA
| | - Adnan Moussalli
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia.,Sciences Department, Museums Victoria, Melbourne, Victoria, Australia
| | - Kevin C Rowe
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia.,Sciences Department, Museums Victoria, Melbourne, Victoria, Australia
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6
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Breed WG, Ding X, Tuke J, Leigh C. Morphological diversity of the spermatozoon and male reproductive tract in Australian Hopping mice, genus
Notomys
– is it determined by sexual selection? J Zool (1987) 2020. [DOI: 10.1111/jzo.12779] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- W. G. Breed
- School of Biological Sciences Faculty of Sciences and The Robinson Research Institute The University of Adelaide Adelaide SA Australia
| | - X. Ding
- Adelaide Medical School Faculty of Health and Medical Sciences The University of Adelaide Adelaide SA Australia
| | - J. Tuke
- School of Mathematical Sciences The University of Adelaide SA Australia
| | - C.M. Leigh
- Adelaide Medical School Faculty of Health and Medical Sciences The University of Adelaide Adelaide SA Australia
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Breed WG, Hassan H, Gonzalez M, McLennan HJ, Leigh CM, Heaney LR. Interspecific diversity of testes mass and sperm morphology in the Philippine chrotomyine rodents: implications for differences in breeding systems across the species. Reprod Fertil Dev 2019; 31:705-711. [PMID: 30475689 DOI: 10.1071/rd18278] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 10/23/2018] [Indexed: 01/16/2023] Open
Abstract
The high diversity of native Philippine murid rodents includes an old endemic group, the chrotomyines, which are the sister group of the Australasian hydromyines. Herein we detail their interspecific diversity of relative testes mass (RTM) and sperm morphology. We find that in chrotomyines, as in the Australasian hydromyines, testes mass relative to body mass differs by an order of magnitude across the species and ranges from a large RTM in Soricomys and Chrotomys species to a small RTM in Apomys. Sperm morphology is associated with these findings, with individuals in species of Soricomys and Chrotomys producing relatively larger spermatozoa with a prominent apical hook and long tail, whereas, by contrast, the Apomys species have a sperm head that either has a very short or no apical hook and a shorter tail. These findings indicate coevolution of RTM with sperm morphological traits across the species, with the marked interspecific differences in RTM suggesting differences in the intensity of intermale sperm competition and hence breeding system. Thus, we hypothesise that species of Soricomys and Chrotomys that produce more streamlined spermatozoa with longer tails have a polyandrous or promiscuous mating system, whereas the Apomys species, which produce smaller and less streamlined spermatozoa, may exhibit monogamy.
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Affiliation(s)
- William G Breed
- Robinson Research Institute, School of Medicine, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Hazirah Hassan
- Robinson Research Institute, School of Medicine, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Macarena Gonzalez
- Robinson Research Institute, School of Medicine, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Hanna J McLennan
- Robinson Research Institute, School of Medicine, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Chris M Leigh
- Robinson Research Institute, School of Medicine, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Lawrence R Heaney
- Field Museum of Natural History, Division of Mammals, 1400 South Lake Shore Drive, Chicago, Illinois 60605, USA
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Roldan ERS. Sperm competition and the evolution of sperm form and function in mammals. Reprod Domest Anim 2019; 54 Suppl 4:14-21. [DOI: 10.1111/rda.13552] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 08/15/2019] [Accepted: 08/16/2019] [Indexed: 12/16/2022]
Affiliation(s)
- Eduardo R. S. Roldan
- Department of Biodiversity and Evolutionary Biology; Museo Nacional de Ciencias Naturales (CSIC); Madrid Spain
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Peirce EJ, McLennan HJ, Tuke J, Leigh CM, Breed WG. Evolution of the testis and spermatozoon in mice and rats (Subfamily
Murinae
) in the absence of sperm competition. J Zool (1987) 2018. [DOI: 10.1111/jzo.12573] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- E. J. Peirce
- Adelaide Medical School Faculty of Health and Medical Sciences The University of Adelaide Adelaide SA Australia
| | - H. J. McLennan
- Adelaide Medical School Faculty of Health and Medical Sciences The University of Adelaide Adelaide SA Australia
| | - J. Tuke
- School of Mathematical Sciences The University of Adelaide Adelaide SA Australia
| | - C. M. Leigh
- Adelaide Medical School Faculty of Health and Medical Sciences The University of Adelaide Adelaide SA Australia
| | - W. G. Breed
- School of Biological Sciences Faculty of Sciences The University of Adelaide Adelaide SA Australia
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Larson EL, Kopania EEK, Good JM. Spermatogenesis and the Evolution of Mammalian Sex Chromosomes. Trends Genet 2018; 34:722-732. [PMID: 30077434 PMCID: PMC6161750 DOI: 10.1016/j.tig.2018.06.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 06/20/2018] [Accepted: 06/21/2018] [Indexed: 12/23/2022]
Abstract
Developmental constraint and sexual conflict shape the evolution of heteromorphic sex chromosomes. These contrasting forces are perhaps strongest during spermatogenesis in species with XY males. In this review, we consider how the unique regulatory environment and selective pressures of spermatogenesis interact to impact sex chromosome evolution in mammals. We explore how each developmental phase of spermatogenesis influences sex chromosome gene content, structure, and rate of molecular evolution, and how these attributes may contribute to speciation. We argue that a developmental context is fundamental to understanding sex chromosome evolution and that an evolutionary perspective can shed new light on our understanding of sperm development.
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Affiliation(s)
- Erica L Larson
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA.
| | - Emily E K Kopania
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Jeffrey M Good
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
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Ferres KM, McPherson NO, Lane M, Bakos HW, Kind KL, Breed WG. Gamete cryopreservation of Australian 'old endemic' rodents – spermatozoa from the plains mouse (Pseudomys
australis) and spinifex hopping mouse (Notomys alexis). AUSTRALIAN MAMMALOGY 2018. [DOI: 10.1071/am16055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Most of the Australian ‘old endemic’ rodents have greatly reduced distributions with several species now threatened with extinction. Application of assisted reproductive technology has the potential to assist in their conservation programs in at least a few species. Here we describe an attempt to cryopreserve spermatozoa from two of these species – those of the plains mouse (Pseudomys australis) and spinifex hopping mouse (Notomys alexis), which have dramatic differences in sperm morphology. Slow and rapid freezing and three different cryoprotectant media with either raffinose, glycerol and/or skim milk were used and the results compared with those of house mouse sperm, which were used as controls. Sperm morphology, motility, membrane integrity and DNA damage were determined. Prior to cryopreservation there was a higher percentage of morphologically normal, motile, P. australis sperm than in those from N. alexis. Following cryopreservation, regardless of treatment, the percentage of motile sperm was low but it was higher when raffinose with skim milk was used as a cryoprotectant than in raffinose with glycerol albeit that minimal differences in membrane integrity or DNA damage were evident. Raffinose with skim milk should thus be used as a cryoprotectant for storing sperm of these Australian rodents in the future.
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Pahl T, McLennan HJ, Wang Y, Achmadi AS, Rowe KC, Aplin K, Breed WG. Sperm morphology of the Rattini – are the interspecific differences due to variation in intensity of intermale sperm competition? Reprod Fertil Dev 2018; 30:1434-1442. [DOI: 10.1071/rd17431] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 04/05/2018] [Indexed: 01/16/2023] Open
Abstract
It is widely accepted that in mammals a causal relationship exists between postcopulatory sexual selection and relative testes mass of the species concerned, but how much it determines sperm size and shape is debatable. Here we detailed for the largest murine rodent tribe, the Rattini, the interspecific differences in relative testes mass and sperm form. We found that residual testes mass correlates with sperm head apical hook length as well as its angle, together with tail length, and that within several lineages a few species have evolved highly divergent sperm morphology with a reduced or absent apical hook and shorter tail. Although most species have a relative testes mass of 1–4%, these derived sperm traits invariably co-occur in species with much smaller relative testes mass. We therefore suggest that high levels of intermale sperm competition maintain a sperm head with a long apical hook and long tail, whereas low levels of intermale sperm competition generally result in divergent sperm heads with a short or non-existent apical hook and shorter tail. We thus conclude that sexual selection is a major selective force in driving sperm head form and tail length in this large tribe of murine rodents.
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