scholarly journals Germline-Specific Repetitive Elements in Programmatically Eliminated Chromosomes of the Sea Lamprey (Petromyzon marinus)

Genes ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 832
Author(s):  
Vladimir A. Timoshevskiy ◽  
Nataliya Y. Timoshevskaya ◽  
Jeramiah J. Smith
Keyword(s):  
Large Scale ◽  
Petromyzon Marinus ◽  
Repetitive Sequences ◽  
Chromosome Elimination ◽  
Sea Lamprey ◽  
Repetitive Elements ◽  
Integrative Approach ◽  
Specific Subset ◽  
Dna Elimination ◽  
Germline Genes

The sea lamprey (Petromyzon marinus) is one of few vertebrate species known to reproducibly eliminate large fractions of its genome during normal embryonic development. This germline-specific DNA is lost in the form of large fragments, including entire chromosomes, and available evidence suggests that DNA elimination acts as a permanent silencing mechanism that prevents the somatic expression of a specific subset of “germline” genes. However, reconstruction of eliminated regions has proven to be challenging due to the complexity of the lamprey karyotype. We applied an integrative approach aimed at further characterization of the large-scale structure of eliminated segments, including: (1) in silico identification of germline-enriched repeats; (2) mapping the chromosomal location of specific repetitive sequences in germline metaphases; and (3) 3D DNA/DNA-hybridization to embryonic lagging anaphases, which permitted us to both verify the specificity of elements to physically eliminated chromosomes and characterize the subcellular organization of these elements during elimination. This approach resulted in the discovery of several repetitive elements that are found exclusively on the eliminated chromosomes, which subsequently permitted the identification of 12 individual chromosomes that are programmatically eliminated during early embryogenesis. The fidelity and specificity of these highly abundant sequences, their distinctive patterning in eliminated chromosomes, and subcellular localization in elimination anaphases suggest that these sequences might contribute to the specific targeting of chromosomes for elimination or possibly in molecular interactions that mediate their decelerated poleward movement in chromosome elimination anaphases, isolation into micronuclei and eventual degradation.

scholarly journals Content of and interactions between repetitive elements in programmatically eliminated chromosomes of the sea lamprey (Petromyzon marinus)

2019 ◽  
Author(s):  
Vladimir A. Timoshevskiy ◽  
Nataliya Y. Timoshevskaya ◽  
Jeramiah J. Smith
Keyword(s):  
Large Scale ◽  
Genome Rearrangement ◽  
Petromyzon Marinus ◽  
Repetitive Sequences ◽  
Sea Lamprey ◽  
Repetitive Elements ◽  
Integrative Approach ◽  
Vertebrate Species ◽  
Repeat Content ◽  
Specific Subset

ABSTRACTThe sea lamprey (Petromyzon marinus) is one of few vertebrate species that is known to reproducibly eliminate large fractions of its genome during normal embryonic development. In lamprey, elimination events are initiated at the 6thembryonic cleavage and result in the loss of ∼20% of an embryo’s genomic DNA from essentially all somatic cell lineages (these same sequences are retained in the germline). This germline-specific DNA is lost in the form of large fragments, including entire chromosomes, and available evidence suggests that DNA elimination acts as a permanent silencing mechanism that prevents the somatic expression of a specific subset of “germline” genes. However, reconstruction of eliminated regions has proven challenging due to the complexity of the lamprey karyotype (84 small pairs of somatic chromosomes and ∼100 pairs of germline chromosomes), the exceedingly high repeat content of the genome and even higher repeat content of eliminated fragments.We applied an integrative approach aimed at further characterization of the large-scale structure of eliminated segments, including: 1)in silicoidentification of germline-enriched repeats; mapping the chromosomal location of specific repetitive sequences in germline metaphases, and verification of repeat specificity to eliminated chromosomes by 3D DNA/DNA-hybridization to embryonic lagging anaphases. Our integrative approach resulted in the discovery of multiple highly abundant repetitive elements that are found exclusively on the eliminated (germline-specific) chromosomes which in turn permitted the identification of 12 individual chromosomes that are programmatically eliminated during early embryogenesis. The fidelity of germline-specific repetitive elements and their distinctive patterning in elimination anaphases are taken as evidence that these sequences might contribute to the specific targeting of chromosomes for elimination and possibly in molecular interactions that mediate their decelerated poleward movement in chromosome elimination anaphases, isolation from the primary nuclei and eventual degradation.AUTHOR SUMMARYEpigenetic silencing methods provide a means of precisely restricting gene expression while maintaining the integrity of the genomic template that encodes this information, and are employed by diverse species throughout the tree of life. Programmed genome rearrangement (PGR) represents a parallel approach that maintains genome integrity across generations but alters the genomes of cells within an organism. To better resolve elimination events that take place during PGR in the sea lamprey (one of few vertebrate species known to undergo large scale PGR) we sought to identify sequences that define specific eliminated chromosomes. Using computational predictions and cytogenetic validation, we identified six new repetitive elements that are restricted to the eliminated chromosomes and permit the identification of twelve distinct eliminated chromosomes. Analysis of these repeats in meiotic testes and in embryos sampled during the process of elimination shows that these repeats localize to specific subcellular regions, and suggest a potential role of these repetitive elements in targeting chromosomes for silencing via elimination.

Effects of Control of the Sea Lamprey (Petromyzon marinus) on Migratory and Resident Fish Populations

1980 ◽  
Vol 37 (11) ◽  
pp. 1886-1894 ◽  
Author(s):  
F. H. Dahl ◽  
R. B. McDonald
Keyword(s):  
Large Scale ◽  
Petromyzon Marinus ◽  
Sea Lamprey ◽  
Fish Populations ◽  
Long Term Effects ◽  
Migratory Species ◽  
Chemical Treatments ◽  
Catostomus Catostomus ◽  
Noturus Flavus

Information from the records of the various agencies on control of the sea lamprey (Petromyzon marinus) was summarized from the early approach to control by mechanical or electrical barriers and chemical toxicants. While fish kill has been an inescapable consequence of the program, information available for migratory species has shown no large-scale detrimental effects. The only reportable instance of damage to a resident stream species has been the near loss of the stonecat (Noturus flavus) from tributaries to the southwest corner of Lake Superior, resulting from chemical treatments. Although no similar occurrences were recognized, available documentation proved inadequate to record long-term effects on these vulnerable species. As long as existing control methods continue, no matter the precautions taken, fish populations will be affected. Whether or not this remains a tenable situation is a question for this symposium and the future.Key words: weirs, chemicals, fish kills, sea lamprey, Petromyzon marinus; Catostomus catostomus, Catostomus commersoni, Noturus flavus, Salvelinus fontinalis

scholarly journals A pheromone outweighs temperature in influencing migration of sea lamprey

2015 ◽  
Vol 2 (5) ◽  
pp. 150009 ◽  
Author(s):  
Cory O. Brant ◽  
Ke Li ◽  
Nicholas S. Johnson ◽  
Weiming Li
Keyword(s):  
Large Scale ◽  
Petromyzon Marinus ◽  
Sea Lamprey ◽  
Mature Male ◽  
Reliable Information ◽  
Conflicting Information ◽  
Petromyzonol Sulfate ◽  
Sea Lampreys ◽  
Cold Stream ◽  
Conspecific Cues

Organisms continuously acquire and process information from surrounding cues. While some cues complement one another in delivering more reliable information, others may provide conflicting information. How organisms extract and use reliable information from a multitude of cues is largely unknown. We examined movement decisions of sea lampreys ( Petromyzon marinus L.) exposed to a conspecific and an environmental cue during pre-spawning migration. Specifically, we predicted that the mature male-released sex pheromone 3-keto petromyzonol sulfate (3kPZS) will outweigh the locomotor inhibiting effects of cold stream temperature (less than 15°C). Using large-scale stream bioassays, we found that 3kPZS elicits an increase (more than 40%) in upstream movement of pre-spawning lampreys when the water temperatures were below 15°C. Both warming temperatures and conspecific cues increase upstream movement when the water temperature rose above 15°C. These patterns define an interaction between abiotic and conspecific cues in modulating animal decision-making, providing an example of the hierarchy of contradictory information.

Classification of Sea Lamprey (Petromyzon marinus) Attack Marks on Great Lakes Lake Trout (Salvelinus namaycush)

1980 ◽  
Vol 37 (11) ◽  
pp. 1989-2006 ◽  
Author(s):  
Everett Louis King Jr.
Keyword(s):  
Great Lakes ◽  
Lake Trout ◽  
Petromyzon Marinus ◽  
Attachment Site ◽  
Sea Lamprey ◽  
Salvelinus Namaycush ◽  
Oral Disc ◽  
Field Assessment ◽  
Sea Lampreys

Criteria for the classification of marks inflicted by sea lamprey (Petromyzon marinus) into nine categories were developed from laboratory studies in an attempt to refine the classification system used in field assessment work. These criteria were based on characteristics of the attachment site that could be identified under field conditions by unaided visual means and by touching the attachment site. Healing of these marks was somewhat variable and was influenced by the size of lamprey, duration of attachment, severity of the wound at lamprey detachment, season and water temperature, and by other less obvious factors. Even under laboratory conditions staging of some wounds was difficult, especially at low water temperatures. If these criteria are to be used effectively and with precision in the field, close examination of individual fish may be required. If the feeding and density of specific year-classes of sea lampreys are to be accurately assessed on an annual basis, close attention to the wound size (as it reflects the size of the lamprey's oral disc) and character of wounds on fish will be required as well as consideration of the season of the year in which they are observed.Key words: sea lamprey, attack marks, lake trout, Great Lakes

Evidence that 3-keto petromyzonol sulphate specifically attracts ovulating female sea lamprey, Petromyzon marinus

2005 ◽  
Vol 70 (5) ◽  
pp. 1037-1045 ◽  
Author(s):  
Michael J. Siefkes ◽  
Scott R. Winterstein ◽  
Weiming Li
Keyword(s):  
Petromyzon Marinus ◽  
Sea Lamprey
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