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Optional Endoreplication and Selective Elimination of Parental Genomes during Oogenesis in Diploid and Triploid Hybrid European Water Frogs.

Dedukh D, Litvinchuk S, Rosanov J, Mazepa G, Saifitdinova A, Shabanov D, Krasikova A - PLoS ONE (2015)

Bottom Line: Obtained results allowed us to suggest that during oogenesis the endoreplication involves all genomes occurring before the selective genome elimination.We accepted the hypothesis that only elimination of one copied genome occurs premeiotically in most of triploid hybrid females.Diploid hybrid frogs demonstrate an enlarged frequency of deviations in oogenesis comparatively to triploid hybrids.

View Article: PubMed Central - PubMed

Affiliation: Saint-Petersburg State University, Saint-Petersburg, Russia.

ABSTRACT
Incompatibilities between parental genomes decrease viability of interspecific hybrids; however, deviations from canonical gametogenesis such as genome endoreplication and elimination can rescue hybrid organisms. To evaluate frequency and regularity of genome elimination and endoreplication during gametogenesis in hybrid animals with different ploidy, we examined genome composition in oocytes of di- and triploid hybrid frogs of the Pelophylax esculentus complex. Obtained results allowed us to suggest that during oogenesis the endoreplication involves all genomes occurring before the selective genome elimination. We accepted the hypothesis that only elimination of one copied genome occurs premeiotically in most of triploid hybrid females. At the same time, we rejected the hypothesis stating that the genome of parental species hybrid frogs co-exist with is always eliminated during oogenesis in diploid hybrids. Diploid hybrid frogs demonstrate an enlarged frequency of deviations in oogenesis comparatively to triploid hybrids. Typical for hybrid frogs deviations in gametogenesis increase variability of produced gametes and provide a mechanism for appearance of different forms of hybrids.

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Related in: MedlinePlus

Suggested mechanisms of oogenesis typical for triploid hybrid frogs with RRL genotype and diploid hybrid frogs.(a) During oogenesis of the majority of triploid hybrids with RRL genotype from studied population systems of R-E type, L genome (blue) was eliminated while two remaining R genomes (brown and orange) without endoreplication formed 13 bivalents. (b) In oogenesis of the majority of diploid hybrids with RL genotype from studied population systems of R-E type, L genome (blue) was eliminated and the remaining R genome (orange) was endoreplicated to form 13 bivalents.
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pone.0123304.g003: Suggested mechanisms of oogenesis typical for triploid hybrid frogs with RRL genotype and diploid hybrid frogs.(a) During oogenesis of the majority of triploid hybrids with RRL genotype from studied population systems of R-E type, L genome (blue) was eliminated while two remaining R genomes (brown and orange) without endoreplication formed 13 bivalents. (b) In oogenesis of the majority of diploid hybrids with RL genotype from studied population systems of R-E type, L genome (blue) was eliminated and the remaining R genome (orange) was endoreplicated to form 13 bivalents.

Mentions: In R-E population system, we analyzed genome composition in oocytes of 9 diploid, 13 triploid P. esculentus females with RRL genotype (including females with RLX genotype) and 5 triploid females with LLR genotype. Algorithm to identify the type of genome transmitted in oocytes of hybrid frogs is represented in S1 Material. At first, we describe the chromosomal sets in oocytes of triploid frogs with RRL genotype. We found that 11 females with RRL genotype produced only one type of oocytes with 13 bivalents corresponding to P. ridibundus bivalents (Figs 1a,a` and 2d1–d6`; S1 Movie). Combining the data on hybrid females ploidy and oocyte genome composition, we evaluated appearance of genome elimination and endoreplication events during gametogenesis. We suggest that to form typical oocytes with 13 bivalents corresponding to P. ridibundus bivalents, elimination of L genome occurred premeiotically while two remaining R genomes presumably conjugated during meiosis (Fig 3a).


Optional Endoreplication and Selective Elimination of Parental Genomes during Oogenesis in Diploid and Triploid Hybrid European Water Frogs.

Dedukh D, Litvinchuk S, Rosanov J, Mazepa G, Saifitdinova A, Shabanov D, Krasikova A - PLoS ONE (2015)

Suggested mechanisms of oogenesis typical for triploid hybrid frogs with RRL genotype and diploid hybrid frogs.(a) During oogenesis of the majority of triploid hybrids with RRL genotype from studied population systems of R-E type, L genome (blue) was eliminated while two remaining R genomes (brown and orange) without endoreplication formed 13 bivalents. (b) In oogenesis of the majority of diploid hybrids with RL genotype from studied population systems of R-E type, L genome (blue) was eliminated and the remaining R genome (orange) was endoreplicated to form 13 bivalents.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4403867&req=5

pone.0123304.g003: Suggested mechanisms of oogenesis typical for triploid hybrid frogs with RRL genotype and diploid hybrid frogs.(a) During oogenesis of the majority of triploid hybrids with RRL genotype from studied population systems of R-E type, L genome (blue) was eliminated while two remaining R genomes (brown and orange) without endoreplication formed 13 bivalents. (b) In oogenesis of the majority of diploid hybrids with RL genotype from studied population systems of R-E type, L genome (blue) was eliminated and the remaining R genome (orange) was endoreplicated to form 13 bivalents.
Mentions: In R-E population system, we analyzed genome composition in oocytes of 9 diploid, 13 triploid P. esculentus females with RRL genotype (including females with RLX genotype) and 5 triploid females with LLR genotype. Algorithm to identify the type of genome transmitted in oocytes of hybrid frogs is represented in S1 Material. At first, we describe the chromosomal sets in oocytes of triploid frogs with RRL genotype. We found that 11 females with RRL genotype produced only one type of oocytes with 13 bivalents corresponding to P. ridibundus bivalents (Figs 1a,a` and 2d1–d6`; S1 Movie). Combining the data on hybrid females ploidy and oocyte genome composition, we evaluated appearance of genome elimination and endoreplication events during gametogenesis. We suggest that to form typical oocytes with 13 bivalents corresponding to P. ridibundus bivalents, elimination of L genome occurred premeiotically while two remaining R genomes presumably conjugated during meiosis (Fig 3a).

Bottom Line: Obtained results allowed us to suggest that during oogenesis the endoreplication involves all genomes occurring before the selective genome elimination.We accepted the hypothesis that only elimination of one copied genome occurs premeiotically in most of triploid hybrid females.Diploid hybrid frogs demonstrate an enlarged frequency of deviations in oogenesis comparatively to triploid hybrids.

View Article: PubMed Central - PubMed

Affiliation: Saint-Petersburg State University, Saint-Petersburg, Russia.

ABSTRACT
Incompatibilities between parental genomes decrease viability of interspecific hybrids; however, deviations from canonical gametogenesis such as genome endoreplication and elimination can rescue hybrid organisms. To evaluate frequency and regularity of genome elimination and endoreplication during gametogenesis in hybrid animals with different ploidy, we examined genome composition in oocytes of di- and triploid hybrid frogs of the Pelophylax esculentus complex. Obtained results allowed us to suggest that during oogenesis the endoreplication involves all genomes occurring before the selective genome elimination. We accepted the hypothesis that only elimination of one copied genome occurs premeiotically in most of triploid hybrid females. At the same time, we rejected the hypothesis stating that the genome of parental species hybrid frogs co-exist with is always eliminated during oogenesis in diploid hybrids. Diploid hybrid frogs demonstrate an enlarged frequency of deviations in oogenesis comparatively to triploid hybrids. Typical for hybrid frogs deviations in gametogenesis increase variability of produced gametes and provide a mechanism for appearance of different forms of hybrids.

Show MeSH
Related in: MedlinePlus