26 matches found in 14 documents. Search time: 0.021 seconds. |
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Score: 5.00 | Title: An insertional mutation in the rice PAIR2 gene , the ortholog of Arabidopsis ASY1 , results in a defect in homologous chromosome pairing during meiosis .
| Author: Nonomura KI Nakano M Murata K Miyoshi K Eiguchi M Miyao A Hirochika H Kurata N | Citation: V : 271 ( 2 ) P : 121-9 Year: 2004 Type: ARTICLE | Literature: oryza Field: abstract Doc ID: pub14758540 Accession (PMID): 14758540 | Abstract: To elucidate the genetic system that establishes homologous chromosome pairing in monocot plants , we have isolated an asynaptic mutant of rice , designated pair2 ( homologous pairing aberration in rice meiosis 2 ) , in which 24 completely unpaired univalents are observed at pachytene and diakinesis .
The mutation was caused by an insertion of the retrotransposon Tos17 , as demonstrated by complementation of the mutation by transformation with the corresponding wild-type gene .
The gene in which the element was inserted is orthologous to the ASY1 gene of Arabidopsis thaliana and the HOP1 gene of Saccharomyces cerevisiae .
Mature PAIR2 mRNA and several splicing variants were found to be highly expressed in wild-type reproductive it issues , and lower expression was also detected in vegetative it issues .
In situ hybridization and BrdU incorporation experiments revealed that PAIR2 expression is specifically enhanced in male and female meiocytes , but not in those at pre-meiotic S phase or in the pollen maturation stages .
The results obtained in this study suggest that the PAIR2 gene is essential for homologous chromosome pairing in meiosis , as in the case of the genes ASY1 and HOP1 .
The study also suggested the possibility that a highly homologous copy of the PAIR2 gene located on a different chromosome is in fact a pseudogene . | Matching Sentences: [ Sen. 1, subscore: 1.00 ]: To elucidate the genetic system that establishes homologous chromosome pairing in monocot plants , we have isolated an asynaptic mutant of rice , designated pair2 ( homologous pairing aberration in rice meiosis 2 ) , in which 24 completely unpaired univalents are observed at pachytene and diakinesis . The mutation was caused by an insertion of the retrotransposon Tos17 , as demonstrated by complementation of the mutation by transformation with the corresponding wild-type gene . The gene in which the element was inserted is orthologous to the ASY1 gene of Arabidopsis thaliana and the HOP1 gene of Saccharomyces cerevisiae . Mature PAIR2 mRNA and several splicing variants were found to be highly expressed in wild-type reproductive it issues , and lower expression was also detected in vegetative it issues . In situ hybridization and BrdU incorporation experiments revealed that PAIR2 expression is specifically enhanced in male and female meiocytes , but not in those at pre-meiotic S phase or in the pollen maturation stages . The results obtained in this study suggest that the PAIR2 gene is essential for homologous chromosome pairing in meiosis , as in the case of the genes ASY1 and HOP1 . The study also suggested the possibility that a highly homologous copy of the PAIR2 gene located on a different chromosome is in fact a pseudogene . [ Sen. 4, subscore: 1.00 ]: To elucidate the genetic system that establishes homologous chromosome pairing in monocot plants , we have isolated an asynaptic mutant of rice , designated pair2 ( homologous pairing aberration in rice meiosis 2 ) , in which 24 completely unpaired univalents are observed at pachytene and diakinesis . The mutation was caused by an insertion of the retrotransposon Tos17 , as demonstrated by complementation of the mutation by transformation with the corresponding wild-type gene . The gene in which the element was inserted is orthologous to the ASY1 gene of Arabidopsis thaliana and the HOP1 gene of Saccharomyces cerevisiae . Mature PAIR2 mRNA and several splicing variants were found to be highly expressed in wild-type reproductive it issues , and lower expression was also detected in vegetative it issues . In situ hybridization and BrdU incorporation experiments revealed that PAIR2 expression is specifically enhanced in male and female meiocytes , but not in those at pre-meiotic S phase or in the pollen maturation stages . The results obtained in this study suggest that the PAIR2 gene is essential for homologous chromosome pairing in meiosis , as in the case of the genes ASY1 and HOP1 . The study also suggested the possibility that a highly homologous copy of the PAIR2 gene located on a different chromosome is in fact a pseudogene . [ Sen. 5, subscore: 1.00 ]: To elucidate the genetic system that establishes homologous chromosome pairing in monocot plants , we have isolated an asynaptic mutant of rice , designated pair2 ( homologous pairing aberration in rice meiosis 2 ) , in which 24 completely unpaired univalents are observed at pachytene and diakinesis . The mutation was caused by an insertion of the retrotransposon Tos17 , as demonstrated by complementation of the mutation by transformation with the corresponding wild-type gene . The gene in which the element was inserted is orthologous to the ASY1 gene of Arabidopsis thaliana and the HOP1 gene of Saccharomyces cerevisiae . Mature PAIR2 mRNA and several splicing variants were found to be highly expressed in wild-type reproductive it issues , and lower expression was also detected in vegetative it issues . In situ hybridization and BrdU incorporation experiments revealed that PAIR2 expression is specifically enhanced in male and female meiocytes , but not in those at pre-meiotic S phase or in the pollen maturation stages . The results obtained in this study suggest that the PAIR2 gene is essential for homologous chromosome pairing in meiosis , as in the case of the genes ASY1 and HOP1 . The study also suggested the possibility that a highly homologous copy of the PAIR2 gene located on a different chromosome is in fact a pseudogene . [ Sen. 6, subscore: 1.00 ]: To elucidate the genetic system that establishes homologous chromosome pairing in monocot plants , we have isolated an asynaptic mutant of rice , designated pair2 ( homologous pairing aberration in rice meiosis 2 ) , in which 24 completely unpaired univalents are observed at pachytene and diakinesis . The mutation was caused by an insertion of the retrotransposon Tos17 , as demonstrated by complementation of the mutation by transformation with the corresponding wild-type gene . The gene in which the element was inserted is orthologous to the ASY1 gene of Arabidopsis thaliana and the HOP1 gene of Saccharomyces cerevisiae . Mature PAIR2 mRNA and several splicing variants were found to be highly expressed in wild-type reproductive it issues , and lower expression was also detected in vegetative it issues . In situ hybridization and BrdU incorporation experiments revealed that PAIR2 expression is specifically enhanced in male and female meiocytes , but not in those at pre-meiotic S phase or in the pollen maturation stages . The results obtained in this study suggest that the PAIR2 gene is essential for homologous chromosome pairing in meiosis , as in the case of the genes ASY1 and HOP1 . The study also suggested the possibility that a highly homologous copy of the PAIR2 gene located on a different chromosome is in fact a pseudogene . [ Sen. 7, subscore: 1.00 ]: To elucidate the genetic system that establishes homologous chromosome pairing in monocot plants , we have isolated an asynaptic mutant of rice , designated pair2 ( homologous pairing aberration in rice meiosis 2 ) , in which 24 completely unpaired univalents are observed at pachytene and diakinesis . The mutation was caused by an insertion of the retrotransposon Tos17 , as demonstrated by complementation of the mutation by transformation with the corresponding wild-type gene . The gene in which the element was inserted is orthologous to the ASY1 gene of Arabidopsis thaliana and the HOP1 gene of Saccharomyces cerevisiae . Mature PAIR2 mRNA and several splicing variants were found to be highly expressed in wild-type reproductive it issues , and lower expression was also detected in vegetative it issues . In situ hybridization and BrdU incorporation experiments revealed that PAIR2 expression is specifically enhanced in male and female meiocytes , but not in those at pre-meiotic S phase or in the pollen maturation stages . The results obtained in this study suggest that the PAIR2 gene is essential for homologous chromosome pairing in meiosis , as in the case of the genes ASY1 and HOP1 . The study also suggested the possibility that a highly homologous copy of the PAIR2 gene located on a different chromosome is in fact a pseudogene .
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Score: 6.00 | Title: PAIR2 is essential for homologous chromosome synapsis in rice meiosis I | Author: Nonomura K Nakano M Eiguchi M Suzuki T Kurata N | Citation: V : 119 ( Pt 2 ) P : 217-25 Year: 2006 Type: ARTICLE | Literature: oryza Field: abstract Doc ID: pub16410547 Accession (PMID): 16410547 | Abstract: The PAIR2 gene is required for homologous chromosome synapsis at meiosis I in rice ( Oryza sativa L ) and encodes a HORMA-domain protein that is homologous to Saccharomyces cerevisiae HOP1 and Arabidopsis ASY1 .
Immunocytological and electron microscopic analyses indicate that PAIR2 proteins associate with axial elements ( AEs ) at leptotene and zygotene , and is removed from the AEs of arm regions when homologous chromosomes have been synapsed .
Immunocytology against a centromeric histone H3 variant revealed that PAIR2 remains at centromeres until diakinesis , by which time the homologous centromeres had already been synapsed .
However , neither precocious segregation of sister chromatids nor kinetochore dysfunction is observed , and AEs are normally assembled in the mutant .
In the pair2-null mutant , homologous chromosome synapsis is completely eliminated .
This study provides the first description of AE-associated protein in monocot plants and indicates that PAIR2 plays an essential role in promoting homologous chromosome synapsis .
However , PAIR2 does not play a role in AE formation , sister chromatid cohesion at centromeres or kinetochore assembly in meiosis I of rice . | Matching Sentences: [ Sen. 1, subscore: 1.00 ]: The PAIR2 gene is required for homologous chromosome synapsis at meiosis I in rice ( Oryza sativa L ) and encodes a HORMA-domain protein that is homologous to Saccharomyces cerevisiae HOP1 and Arabidopsis ASY1 . Immunocytological and electron microscopic analyses indicate that PAIR2 proteins associate with axial elements ( AEs ) at leptotene and zygotene , and is removed from the AEs of arm regions when homologous chromosomes have been synapsed . Immunocytology against a centromeric histone H3 variant revealed that PAIR2 remains at centromeres until diakinesis , by which time the homologous centromeres had already been synapsed . However , neither precocious segregation of sister chromatids nor kinetochore dysfunction is observed , and AEs are normally assembled in the mutant . In the pair2-null mutant , homologous chromosome synapsis is completely eliminated . This study provides the first description of AE-associated protein in monocot plants and indicates that PAIR2 plays an essential role in promoting homologous chromosome synapsis . However , PAIR2 does not play a role in AE formation , sister chromatid cohesion at centromeres or kinetochore assembly in meiosis I of rice . [ Sen. 2, subscore: 1.00 ]: The PAIR2 gene is required for homologous chromosome synapsis at meiosis I in rice ( Oryza sativa L ) and encodes a HORMA-domain protein that is homologous to Saccharomyces cerevisiae HOP1 and Arabidopsis ASY1 . Immunocytological and electron microscopic analyses indicate that PAIR2 proteins associate with axial elements ( AEs ) at leptotene and zygotene , and is removed from the AEs of arm regions when homologous chromosomes have been synapsed . Immunocytology against a centromeric histone H3 variant revealed that PAIR2 remains at centromeres until diakinesis , by which time the homologous centromeres had already been synapsed . However , neither precocious segregation of sister chromatids nor kinetochore dysfunction is observed , and AEs are normally assembled in the mutant . In the pair2-null mutant , homologous chromosome synapsis is completely eliminated . This study provides the first description of AE-associated protein in monocot plants and indicates that PAIR2 plays an essential role in promoting homologous chromosome synapsis . However , PAIR2 does not play a role in AE formation , sister chromatid cohesion at centromeres or kinetochore assembly in meiosis I of rice . [ Sen. 3, subscore: 1.00 ]: The PAIR2 gene is required for homologous chromosome synapsis at meiosis I in rice ( Oryza sativa L ) and encodes a HORMA-domain protein that is homologous to Saccharomyces cerevisiae HOP1 and Arabidopsis ASY1 . Immunocytological and electron microscopic analyses indicate that PAIR2 proteins associate with axial elements ( AEs ) at leptotene and zygotene , and is removed from the AEs of arm regions when homologous chromosomes have been synapsed . Immunocytology against a centromeric histone H3 variant revealed that PAIR2 remains at centromeres until diakinesis , by which time the homologous centromeres had already been synapsed . However , neither precocious segregation of sister chromatids nor kinetochore dysfunction is observed , and AEs are normally assembled in the mutant . In the pair2-null mutant , homologous chromosome synapsis is completely eliminated . This study provides the first description of AE-associated protein in monocot plants and indicates that PAIR2 plays an essential role in promoting homologous chromosome synapsis . However , PAIR2 does not play a role in AE formation , sister chromatid cohesion at centromeres or kinetochore assembly in meiosis I of rice . [ Sen. 5, subscore: 1.00 ]: The PAIR2 gene is required for homologous chromosome synapsis at meiosis I in rice ( Oryza sativa L ) and encodes a HORMA-domain protein that is homologous to Saccharomyces cerevisiae HOP1 and Arabidopsis ASY1 . Immunocytological and electron microscopic analyses indicate that PAIR2 proteins associate with axial elements ( AEs ) at leptotene and zygotene , and is removed from the AEs of arm regions when homologous chromosomes have been synapsed . Immunocytology against a centromeric histone H3 variant revealed that PAIR2 remains at centromeres until diakinesis , by which time the homologous centromeres had already been synapsed . However , neither precocious segregation of sister chromatids nor kinetochore dysfunction is observed , and AEs are normally assembled in the mutant . In the pair2-null mutant , homologous chromosome synapsis is completely eliminated . This study provides the first description of AE-associated protein in monocot plants and indicates that PAIR2 plays an essential role in promoting homologous chromosome synapsis . However , PAIR2 does not play a role in AE formation , sister chromatid cohesion at centromeres or kinetochore assembly in meiosis I of rice . [ Sen. 6, subscore: 1.00 ]: The PAIR2 gene is required for homologous chromosome synapsis at meiosis I in rice ( Oryza sativa L ) and encodes a HORMA-domain protein that is homologous to Saccharomyces cerevisiae HOP1 and Arabidopsis ASY1 . Immunocytological and electron microscopic analyses indicate that PAIR2 proteins associate with axial elements ( AEs ) at leptotene and zygotene , and is removed from the AEs of arm regions when homologous chromosomes have been synapsed . Immunocytology against a centromeric histone H3 variant revealed that PAIR2 remains at centromeres until diakinesis , by which time the homologous centromeres had already been synapsed . However , neither precocious segregation of sister chromatids nor kinetochore dysfunction is observed , and AEs are normally assembled in the mutant . In the pair2-null mutant , homologous chromosome synapsis is completely eliminated . This study provides the first description of AE-associated protein in monocot plants and indicates that PAIR2 plays an essential role in promoting homologous chromosome synapsis . However , PAIR2 does not play a role in AE formation , sister chromatid cohesion at centromeres or kinetochore assembly in meiosis I of rice . [ Sen. 7, subscore: 1.00 ]: The PAIR2 gene is required for homologous chromosome synapsis at meiosis I in rice ( Oryza sativa L ) and encodes a HORMA-domain protein that is homologous to Saccharomyces cerevisiae HOP1 and Arabidopsis ASY1 . Immunocytological and electron microscopic analyses indicate that PAIR2 proteins associate with axial elements ( AEs ) at leptotene and zygotene , and is removed from the AEs of arm regions when homologous chromosomes have been synapsed . Immunocytology against a centromeric histone H3 variant revealed that PAIR2 remains at centromeres until diakinesis , by which time the homologous centromeres had already been synapsed . However , neither precocious segregation of sister chromatids nor kinetochore dysfunction is observed , and AEs are normally assembled in the mutant . In the pair2-null mutant , homologous chromosome synapsis is completely eliminated . This study provides the first description of AE-associated protein in monocot plants and indicates that PAIR2 plays an essential role in promoting homologous chromosome synapsis . However , PAIR2 does not play a role in AE formation , sister chromatid cohesion at centromeres or kinetochore assembly in meiosis I of rice .
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Score: 5.00 | Title: MER3 is required for normal meiotic crossover formation , but not for presynaptic alignment in rice .
| Author: Wang K Tang D Wang M Lu J Yu H Liu J Qian B Gong Z Wang X Chen J Gu M Cheng Z | Citation: V : P : Year: 2009 Type: Publisher | Literature: oryza Field: abstract Doc ID: pub19470578 Accession (PMID): 19470578 | Abstract: MER3 , a ZMM protein , is required for the formation of crossovers in Saccharomyces cerevisiae and Arabidopsis .
Here , MER3 , the first identified ZMM gene in a monocot , is characterized by map-based cloning in rice ( Oryza sativa ) .
The null mutation of MER3 results in complete sterility without any vegetative defects .
Cytological analyses show that chiasma frequency is reduced dramatically in mer3 mutants and the remaining chiasmata distribute randomly among different pollen mother cells , implying possible coexistence of two kinds of crossover in rice .
Immunocytological analyses reveal that MER3 only exists as foci in prophase I meiocytes .
In addition , MER3 does not colocalize with PAIR2 at the beginning of prophase I , but locates on one end of PAIR2 fragments at later stages , whereas MER3 foci merely locate on one end of REC8 fragments when signals start to be seen in early prophase I The normal loading of PAIR2 and REC8 in mer3 implies that their loading is independent of MER3 .
On the contrary , the absence of MER3 signal in pair2 mutants indicates that PAIR2 is essential for the loading and further function of MER3 .
| Matching Sentences: [ Sen. 6, subscore: 3.00 ]: MER3 , a ZMM protein , is required for the formation of crossovers in Saccharomyces cerevisiae and Arabidopsis . Here , MER3 , the first identified ZMM gene in a monocot , is characterized by map-based cloning in rice ( Oryza sativa ) . The null mutation of MER3 results in complete sterility without any vegetative defects . Cytological analyses show that chiasma frequency is reduced dramatically in mer3 mutants and the remaining chiasmata distribute randomly among different pollen mother cells , implying possible coexistence of two kinds of crossover in rice . Immunocytological analyses reveal that MER3 only exists as foci in prophase I meiocytes . In addition , MER3 does not colocalize with PAIR2 at the beginning of prophase I , but locates on one end of PAIR2 fragments at later stages , whereas MER3 foci merely locate on one end of REC8 fragments when signals start to be seen in early prophase I The normal loading of PAIR2 and REC8 in mer3 implies that their loading is independent of MER3 . On the contrary , the absence of MER3 signal in pair2 mutants indicates that PAIR2 is essential for the loading and further function of MER3 . [ Sen. 7, subscore: 2.00 ]: MER3 , a ZMM protein , is required for the formation of crossovers in Saccharomyces cerevisiae and Arabidopsis . Here , MER3 , the first identified ZMM gene in a monocot , is characterized by map-based cloning in rice ( Oryza sativa ) . The null mutation of MER3 results in complete sterility without any vegetative defects . Cytological analyses show that chiasma frequency is reduced dramatically in mer3 mutants and the remaining chiasmata distribute randomly among different pollen mother cells , implying possible coexistence of two kinds of crossover in rice . Immunocytological analyses reveal that MER3 only exists as foci in prophase I meiocytes . In addition , MER3 does not colocalize with PAIR2 at the beginning of prophase I , but locates on one end of PAIR2 fragments at later stages , whereas MER3 foci merely locate on one end of REC8 fragments when signals start to be seen in early prophase I The normal loading of PAIR2 and REC8 in mer3 implies that their loading is independent of MER3 . On the contrary , the absence of MER3 signal in pair2 mutants indicates that PAIR2 is essential for the loading and further function of MER3 .
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Score: 1.00 | Title: The central element protein ZEP1 of the synaptonemal complex regulates the number of crossovers during meiosis in rice .
| Author: Wang M Wang K Tang D Wei C Li M Shen Y Chi Z Gu M Cheng Z | Citation: V : 22 P : 417-30 Year: 2010 Type: MEDLINE | Literature: oryza Field: abstract Doc ID: pub20154151 Accession (PMID): 20154151 | Abstract: ZEP1 , a transverse filament ( TF ) protein , is the rice ( Oryza sativa ) homolog of Arabidopsis thaliana ZYP1 .
In the Tos17-insertional zep1 mutants , homologous chromosomes align along the entire length of the chromosome , but the synaptonemal complex is not assembled in early prophase I Crossovers are well formed , and 12 bivalents could be detected from diakinesis to metaphase I , which leads to equal chromosomal segregation in anaphase I Moreover , the number of crossovers has a tendency to be increased compared with that in the wild type .
These phenomena are different from the TF mutants identified so far in other organisms .
Chiasma terminalization of the bivalent , which occurs frequently in the wild type , seldom occurred in zep1 .
Transmission electron micrographs and immunodetection using an antibody against ZEP1 showed that ZEP1 is the central element of the synaptonemal complex Although PAIR2 and MER3 were loaded normally in zep1 , their dissociation was delayed severely compared with the wild type .
In addition , ZEP1 is reloaded onto chromosomes in early microspores as the chromosome decondense , suggesting that ZEP1 might have other biological functions during this process .
| Matching Sentences: [ Sen. 5, subscore: 1.00 ]: ZEP1 , a transverse filament ( TF ) protein , is the rice ( Oryza sativa ) homolog of Arabidopsis thaliana ZYP1 . In the Tos17-insertional zep1 mutants , homologous chromosomes align along the entire length of the chromosome , but the synaptonemal complex is not assembled in early prophase I Crossovers are well formed , and 12 bivalents could be detected from diakinesis to metaphase I , which leads to equal chromosomal segregation in anaphase I Moreover , the number of crossovers has a tendency to be increased compared with that in the wild type . These phenomena are different from the TF mutants identified so far in other organisms . Chiasma terminalization of the bivalent , which occurs frequently in the wild type , seldom occurred in zep1 . Transmission electron micrographs and immunodetection using an antibody against ZEP1 showed that ZEP1 is the central element of the synaptonemal complex Although PAIR2 and MER3 were loaded normally in zep1 , their dissociation was delayed severely compared with the wild type . In addition , ZEP1 is reloaded onto chromosomes in early microspores as the chromosome decondense , suggesting that ZEP1 might have other biological functions during this process .
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Score: 2.00 | Title: OsSPO11-1 is essential for both homologous chromosome pairing and crossover formation in rice .
| Author: Yu H Wang M Tang D Wang K Chen F Gong Z Gu M Cheng Z | Citation: V : 119 P : 625-36 Year: 2010 Type: MEDLINE | Literature: oryza Field: abstract Doc ID: pub20625906 Accession (PMID): 20625906 | Abstract: Spo11 is a homolog of a subunit of archaebacterial topoisomerase , which catalyzes DNA double-strand breaks and initiates homologous chromosome recombination .
In the present study , we silenced the SPO11-1 gene in rice ( Oryza sativa ) using RNAi .
Rice plants with loss-of-function of OsSPO11-1 have no apparent growth defects during vegetative development , but homologous chromosome pairing and recombination are significantly obstructed .
Telomeres can be assembled as bouquet during the zygotene stage of the OsSPO11-1-deficient plants , just as that in wild type .
Although the two axial-associated proteins , REC8 and PAIR2 , are loaded onto the chromosomes , the depletion of PAIR2 from the chromosomes is much later than in wild type .
The central element of the synaptonemal complex ( SC ) , ZEP1 , does not load onto the chromosomes normally , implying that SC formation is disturbed severely .
The crossover protein , MER3 , isnt efficiently assembled onto chromosomes and the lack of bivalent suggests that crossovers are also affected in the absence of OsSPO11-1 .
Thus , OsSPO11-1 is essential for both homologous chromosomes pairing and crossover formation during meiosis in rice .
| Matching Sentences: [ Sen. 5, subscore: 2.00 ]: Spo11 is a homolog of a subunit of archaebacterial topoisomerase , which catalyzes DNA double-strand breaks and initiates homologous chromosome recombination . In the present study , we silenced the SPO11-1 gene in rice ( Oryza sativa ) using RNAi . Rice plants with loss-of-function of OsSPO11-1 have no apparent growth defects during vegetative development , but homologous chromosome pairing and recombination are significantly obstructed . Telomeres can be assembled as bouquet during the zygotene stage of the OsSPO11-1-deficient plants , just as that in wild type . Although the two axial-associated proteins , REC8 and PAIR2 , are loaded onto the chromosomes , the depletion of PAIR2 from the chromosomes is much later than in wild type . The central element of the synaptonemal complex ( SC ) , ZEP1 , does not load onto the chromosomes normally , implying that SC formation is disturbed severely . The crossover protein , MER3 , isnt efficiently assembled onto chromosomes and the lack of bivalent suggests that crossovers are also affected in the absence of OsSPO11-1 . Thus , OsSPO11-1 is essential for both homologous chromosomes pairing and crossover formation during meiosis in rice .
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