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A complex recombination pattern in the genome of allotetraploid Brassica napus as revealed by a high-density genetic map.

Cai G, Yang Q, Yi B, Fan C, Edwards D, Batley J, Zhou Y - PLoS ONE (2014)

Bottom Line: A better understanding of the evolutionary relationship between B. napus and B. rapa, B. oleracea, as well as Arabidopsis, which has a common ancestor with these three species, will provide valuable information about the generation and evolution of allopolyploidy.Based on the collinear relationship of B. rapa and B. oleracea in the B. napus genetic map, the B. napus genome was found to consist of 70.1% of the skeleton components of the chromosomes of B. rapa and B. oleracea, with 17.7% of sequences derived from reciprocal translocation between homoeologous chromosomes between the A- and C-genome and 3.6% of sequences derived from reciprocal translocation between non-homologous chromosomes at both intra- and inter-genomic levels.The current study thus provides insights into the formation and evolution of the allotetraploid B. napus genome, which will allow for more accurate transfer of genomic information from B. rapa, B. oleracea and Arabidopsis to B. napus.

View Article: PubMed Central - PubMed

Affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China; Key Laboratory of Rapeseed Genetics and Breeding of Agriculture Ministry of China, Huazhong Agricultural University, Wuhan, China.

ABSTRACT
Polyploidy plays a crucial role in plant evolution. Brassica napus (2n = 38, AACC), the most important oil crop in the Brassica genus, is an allotetraploid that originated through natural doubling of chromosomes after the hybridization of its progenitor species, B. rapa (2n = 20, AA) and B. oleracea (2n = 18, CC). A better understanding of the evolutionary relationship between B. napus and B. rapa, B. oleracea, as well as Arabidopsis, which has a common ancestor with these three species, will provide valuable information about the generation and evolution of allopolyploidy. Based on a high-density genetic map with single nucleotide polymorphism (SNP) and simple sequence repeat (SSR) markers, we performed a comparative genomic analysis of B. napus with Arabidopsis and its progenitor species B. rapa and B. oleracea. Based on the collinear relationship of B. rapa and B. oleracea in the B. napus genetic map, the B. napus genome was found to consist of 70.1% of the skeleton components of the chromosomes of B. rapa and B. oleracea, with 17.7% of sequences derived from reciprocal translocation between homoeologous chromosomes between the A- and C-genome and 3.6% of sequences derived from reciprocal translocation between non-homologous chromosomes at both intra- and inter-genomic levels. The current study thus provides insights into the formation and evolution of the allotetraploid B. napus genome, which will allow for more accurate transfer of genomic information from B. rapa, B. oleracea and Arabidopsis to B. napus.

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Conserved blocks of Brassicaceae Ancestral Karyotype on Brassica napus genetic map.For each linkage group (LG), the left vertical bar represents the LG with mapped markers (red dashes for single nucleotide polymorphisms (SNPs) and black for simple sequence repeat (SSR)). The conserved Arabidopsis blocks are listed on the right of each LG. The length of LG bars is proportional to their genetic distances. The conserved blocks are identified according to their positions in the Arabidopsis genome (see Materials and Methods) and depicted with colors based on the Ancestral Karyotype chromosome positions as described by Schranz et al. [9]. Inverted letters for respective conserved blocks indicate inversions in the LGs relative to Arabidopsis chromosomes. The length of each vertical bar for Ancestral karyotype chromosome is proportional to its physical length.
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pone-0109910-g001: Conserved blocks of Brassicaceae Ancestral Karyotype on Brassica napus genetic map.For each linkage group (LG), the left vertical bar represents the LG with mapped markers (red dashes for single nucleotide polymorphisms (SNPs) and black for simple sequence repeat (SSR)). The conserved Arabidopsis blocks are listed on the right of each LG. The length of LG bars is proportional to their genetic distances. The conserved blocks are identified according to their positions in the Arabidopsis genome (see Materials and Methods) and depicted with colors based on the Ancestral Karyotype chromosome positions as described by Schranz et al. [9]. Inverted letters for respective conserved blocks indicate inversions in the LGs relative to Arabidopsis chromosomes. The length of each vertical bar for Ancestral karyotype chromosome is proportional to its physical length.

Mentions: Linkage analysis was conducted with the 2,323 polymorphic loci (1850 SNPs and 473 SSR loci), and 2,115 markers (1667 SNPs and 448 SSR loci) were mapped onto 19 linkage groups (LGs) of B. napus (Table 1, Figure 1, Table S1). The total length of the genetic map was 2,477.4 cM, with an average distance of 1.27 cM between the markers (Table 1). The marker density (1.07 cM/marker) on the A genome of B. napus (designated as BnA-genome thereafter) was higher than that (1.49 cM/marker) on the C genome of B. napus (designated as BnC-genome thereafter).


A complex recombination pattern in the genome of allotetraploid Brassica napus as revealed by a high-density genetic map.

Cai G, Yang Q, Yi B, Fan C, Edwards D, Batley J, Zhou Y - PLoS ONE (2014)

Conserved blocks of Brassicaceae Ancestral Karyotype on Brassica napus genetic map.For each linkage group (LG), the left vertical bar represents the LG with mapped markers (red dashes for single nucleotide polymorphisms (SNPs) and black for simple sequence repeat (SSR)). The conserved Arabidopsis blocks are listed on the right of each LG. The length of LG bars is proportional to their genetic distances. The conserved blocks are identified according to their positions in the Arabidopsis genome (see Materials and Methods) and depicted with colors based on the Ancestral Karyotype chromosome positions as described by Schranz et al. [9]. Inverted letters for respective conserved blocks indicate inversions in the LGs relative to Arabidopsis chromosomes. The length of each vertical bar for Ancestral karyotype chromosome is proportional to its physical length.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4214627&req=5

pone-0109910-g001: Conserved blocks of Brassicaceae Ancestral Karyotype on Brassica napus genetic map.For each linkage group (LG), the left vertical bar represents the LG with mapped markers (red dashes for single nucleotide polymorphisms (SNPs) and black for simple sequence repeat (SSR)). The conserved Arabidopsis blocks are listed on the right of each LG. The length of LG bars is proportional to their genetic distances. The conserved blocks are identified according to their positions in the Arabidopsis genome (see Materials and Methods) and depicted with colors based on the Ancestral Karyotype chromosome positions as described by Schranz et al. [9]. Inverted letters for respective conserved blocks indicate inversions in the LGs relative to Arabidopsis chromosomes. The length of each vertical bar for Ancestral karyotype chromosome is proportional to its physical length.
Mentions: Linkage analysis was conducted with the 2,323 polymorphic loci (1850 SNPs and 473 SSR loci), and 2,115 markers (1667 SNPs and 448 SSR loci) were mapped onto 19 linkage groups (LGs) of B. napus (Table 1, Figure 1, Table S1). The total length of the genetic map was 2,477.4 cM, with an average distance of 1.27 cM between the markers (Table 1). The marker density (1.07 cM/marker) on the A genome of B. napus (designated as BnA-genome thereafter) was higher than that (1.49 cM/marker) on the C genome of B. napus (designated as BnC-genome thereafter).

Bottom Line: A better understanding of the evolutionary relationship between B. napus and B. rapa, B. oleracea, as well as Arabidopsis, which has a common ancestor with these three species, will provide valuable information about the generation and evolution of allopolyploidy.Based on the collinear relationship of B. rapa and B. oleracea in the B. napus genetic map, the B. napus genome was found to consist of 70.1% of the skeleton components of the chromosomes of B. rapa and B. oleracea, with 17.7% of sequences derived from reciprocal translocation between homoeologous chromosomes between the A- and C-genome and 3.6% of sequences derived from reciprocal translocation between non-homologous chromosomes at both intra- and inter-genomic levels.The current study thus provides insights into the formation and evolution of the allotetraploid B. napus genome, which will allow for more accurate transfer of genomic information from B. rapa, B. oleracea and Arabidopsis to B. napus.

View Article: PubMed Central - PubMed

Affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China; Key Laboratory of Rapeseed Genetics and Breeding of Agriculture Ministry of China, Huazhong Agricultural University, Wuhan, China.

ABSTRACT
Polyploidy plays a crucial role in plant evolution. Brassica napus (2n = 38, AACC), the most important oil crop in the Brassica genus, is an allotetraploid that originated through natural doubling of chromosomes after the hybridization of its progenitor species, B. rapa (2n = 20, AA) and B. oleracea (2n = 18, CC). A better understanding of the evolutionary relationship between B. napus and B. rapa, B. oleracea, as well as Arabidopsis, which has a common ancestor with these three species, will provide valuable information about the generation and evolution of allopolyploidy. Based on a high-density genetic map with single nucleotide polymorphism (SNP) and simple sequence repeat (SSR) markers, we performed a comparative genomic analysis of B. napus with Arabidopsis and its progenitor species B. rapa and B. oleracea. Based on the collinear relationship of B. rapa and B. oleracea in the B. napus genetic map, the B. napus genome was found to consist of 70.1% of the skeleton components of the chromosomes of B. rapa and B. oleracea, with 17.7% of sequences derived from reciprocal translocation between homoeologous chromosomes between the A- and C-genome and 3.6% of sequences derived from reciprocal translocation between non-homologous chromosomes at both intra- and inter-genomic levels. The current study thus provides insights into the formation and evolution of the allotetraploid B. napus genome, which will allow for more accurate transfer of genomic information from B. rapa, B. oleracea and Arabidopsis to B. napus.

Show MeSH
Related in: MedlinePlus