The Lamprey Gonad

Docker, Margaret F.; Beamish, F. W. H.; Yasmin, Tahirah; Bryan, Mara B.; Khan, Arfa

doi:10.1007/978-94-024-1684-8_1

Cited by 16 publications

(24 citation statements)

References 420 publications

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“…Although cues to sex determination in lampreys at this stage remain unclear (i.e. environmental versus genetic sex determination) (Docker and Beamish, 1994;Docker et al, 2019;Johnson et al, 2017), those leading to sex differentiation likely depend on gene functions that regulate reproductive physiology. The development and testing of gene editing tools toward perturbing sea lamprey reproductive physiology, for example, by biasing sex ratios and/or reducing fecundity, may offer solutions to this ongoing problem.…”

Section: Gene Editing For Management Of Invasive Sea Lampreymentioning

confidence: 99%

Functional genetic analysis in a jawless vertebrate, the sea lamprey: insights into the developmental evolution of early vertebrates

York

McCauley

2020

Journal of Experimental Biology

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Lampreys and hagfishes are the only surviving relicts of an ancient but ecologically dominant group of jawless fishes that evolved in the seas of the Cambrian era over half a billion years ago. Because of their phylogenetic position as the sister group to all other vertebrates ( jawed vertebrates), comparisons of embryonic development between jawless and jawed vertebrates offers researchers in the field of evolutionary developmental biology the unique opportunity to address fundamental questions related to the nature of our earliest vertebrate ancestors. Here, we describe how genetic analysis of embryogenesis in the sea lamprey (Petromyzon marinus) has provided insight into the origin and evolution of developmentalgenetic programs in vertebrates. We focus on recent work involving CRISPR/Cas9-mediated genome editing to study gene regulatory mechanisms involved in the development and evolution of neural crest cells and new cell types in the vertebrate nervous system, and transient transgenic assays that have been instrumental in dissecting the evolution of cis-regulatory control of gene expression in vertebrates. Finally, we discuss the broad potential for these functional genomic tools to address previously unanswerable questions related to the evolution of genomic regulatory mechanisms as well as issues related to invasive sea lamprey population control.

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Section: Gene Editing For Management Of Invasive Sea Lampreymentioning

confidence: 99%

Functional genetic analysis in a jawless vertebrate, the sea lamprey: insights into the developmental evolution of early vertebrates

York

McCauley

2020

Journal of Experimental Biology

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“…In addition to the idiosyncrasies of their genome, understanding the genetic basis of lamprey sex determination ( i.e. , the “master switch” that determines the ultimate fate of the gonad) and sex differentiation (the process by which the undifferentiated gonad develops into a recognizable ovary or testis) is complicated by their long and complex life cycle, the prolonged period during which their gonads remain histologically undifferentiated, and uncertainties regarding which sex steroids are physiologically relevant (see review by Docker et al 2019 ). Environmental sex determination (ESD) has been proposed in lampreys, but evidence for ESD is equivocal; genes involved in sex determination in the “lower vertebrates” ( i.e.…”

Section: Introductionmentioning

confidence: 99%

“…Environmental sex determination (ESD) has been proposed in lampreys, but evidence for ESD is equivocal; genes involved in sex determination in the “lower vertebrates” ( i.e. , reptiles and non-amniotes) are far less conserved than they are in birds and mammals, and whether there is a genetic component to sex determination is lampreys is unknown ( Docker et al 2019 ). In contrast, many of the genes involved in the sex differentiation process tend to be conserved among vertebrates ( Siegfried 2010 ), and initial studies suggest that at least some of the same genes are involved in gonadal development in lampreys ( Spice et al 2014 ; Khan 2017 ; see below).…”

Section: Introductionmentioning

confidence: 99%

“…In all species, there is a prolonged period during which the single elongated gonad remains histologically undifferentiated, and lampreys are sometimes said to pass through an initial female or intersexual stage, because at least a few small oocytes appear in most larvae regardless of future sex ( Hardisty 1965a , b ; Docker et al 2019 ; Figure 1 ). Meiosis and oocyte growth are more synchronized and extensive in females, and ovarian differentiation is completed during the larval stage (at ∼1–3 years of age).…”

Section: Introductionmentioning

confidence: 99%

“…Histological images on the timeline illustrate where each of the 10 samples used in this study fall in the developmental process. Adapted from Docker et al (2019) .…”

Section: Introductionmentioning

confidence: 99%

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Transcriptomic analysis of gonadal development in parasitic and non-parasitic lampreys (Ichthyomyzonspp.), with a comparison of genomic resources in these non-model species

Ajmani

Yasmin

Docker

et al. 2021

G3 Genes|Genomes|Genetics

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Lampreys are jawless fishes that diverged ∼550 million years ago from other vertebrates. Sequencing of the somatic and germline genomes of the sea lamprey (Petromyzon marinus) in 2013 and 2018, respectively, has helped improve our understanding of the genes and gene networks that control many aspects of lamprey development. However, little is known about the genetic basis of gonadal differentiation in lampreys, partly due to the prolonged period during which their gonads remain sexually indeterminate. We performed RNA-sequencing on gonadal samples from four chestnut lamprey (Ichthyomyzon castaneus) and six northern brook lamprey (I. fossor) to identify differentially expressed genes (DEG’s) and pathways associated with transcriptomic differences in: 1) larvae during early gonadal differentiation versus definitive females (i.e., with oocytes in the slow cytoplasmic growth phase); and 2) females versus definitive males undergoing spermatogonial proliferation. We compared the mapping percentages of these transcriptomes to the two available sea lamprey reference genomes and three annotation files (Ensembl and UCSC for the somatic genome, and SIMRbase for the germline genome). We found that mapping the RNA-seq reads to the germline genome gave superior results and, using Trinotate, we provided new putative annotations for 8,161 genes in the somatic assembly and 880 genes for the germline assembly. We identified >2,000 DEG’s between stages and sexes, as well as biological pathways associated with each. Interestingly, some of the up-regulated genes (e.g., DEG’s associated with spermiation) suggest that changes in gene expression can precede morphological changes by several months. In contrast, only 81 DEG’s were evident between the chestnut lamprey (that remains sexually immature during an extended post-metamorphic parasitic feeding phase) and the non-parasitic northern brook lamprey (that undergoes sexual maturation near the end of metamorphosis), but few replicates were available for comparable stages and sexes. This work lays the foundation for identifying and confirming the orthology and function of genes involved in gonadal development in these and other lamprey species across more developmental stages.

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Synergizing basic and applied scientific approaches to help understand lamprey biology and support management actions

Hume

Bracken

Mateus

et al. 2021

Journal of Great Lakes Research

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The Lamprey Gonad

Cited by 16 publications

References 420 publications

Functional genetic analysis in a jawless vertebrate, the sea lamprey: insights into the developmental evolution of early vertebrates

Functional genetic analysis in a jawless vertebrate, the sea lamprey: insights into the developmental evolution of early vertebrates

Transcriptomic analysis of gonadal development in parasitic and non-parasitic lampreys (Ichthyomyzonspp.), with a comparison of genomic resources in these non-model species

Synergizing basic and applied scientific approaches to help understand lamprey biology and support management actions

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