Limits...
The multipartite mitochondrial genome of Liposcelis bostrychophila: insights into the evolution of mitochondrial genomes in bilateral animals.

Wei DD, Shao R, Yuan ML, Dou W, Barker SC, Wang JJ - PLoS ONE (2012)

Bottom Line: Intriguingly, mt chromosome I is twice as abundant as chromosome II.It appears that the selection pressure for compact mt genomes in bilateral animals favors small mt chromosomes when small mt chromosomes co-exist with the typical large mt chromosomes.Thus, small mt chromosomes may have selective advantages over large mt chromosomes in bilateral animals.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China.

ABSTRACT
Booklice (order Psocoptera) in the genus Liposcelis are major pests to stored grains worldwide and are closely related to parasitic lice (order Phthiraptera). We sequenced the mitochondrial (mt) genome of Liposcelis bostrychophila and found that the typical single mt chromosome of bilateral animals has fragmented into and been replaced by two medium-sized chromosomes in this booklouse; each of these chromosomes has about half of the genes of the typical mt chromosome of bilateral animals. These mt chromosomes are 8,530 bp (mt chromosome I) and 7,933 bp (mt chromosome II) in size. Intriguingly, mt chromosome I is twice as abundant as chromosome II. It appears that the selection pressure for compact mt genomes in bilateral animals favors small mt chromosomes when small mt chromosomes co-exist with the typical large mt chromosomes. Thus, small mt chromosomes may have selective advantages over large mt chromosomes in bilateral animals. Phylogenetic analyses of mt genome sequences of Psocodea (i.e. Psocoptera plus Phthiraptera) indicate that: 1) the order Psocoptera (booklice and barklice) is paraphyletic; and 2) the order Phthiraptera (the parasitic lice) is monophyletic. Within parasitic lice, however, the suborder Ischnocera is paraphyletic; this differs from the traditional view that each suborder of parasitic lice is monophyletic.

Show MeSH

Related in: MedlinePlus

Putative secondary structures of the 20 tRNA genes identified in the mitochondrial genome of Liposcelis bostrychophila.Bars indicate Watson-Crick base pairings, and dots between G and U pairs mark canonical base pairings appearing in RNA.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3316519&req=5

pone-0033973-g004: Putative secondary structures of the 20 tRNA genes identified in the mitochondrial genome of Liposcelis bostrychophila.Bars indicate Watson-Crick base pairings, and dots between G and U pairs mark canonical base pairings appearing in RNA.

Mentions: Sixteen of the 20 tRNA genes in the Beibei strain of L. bostrychophila have the conventional clover-leaf secondary structures (Figure 4). Three tRNA genes, trnR, trnC and trnS1, lack the sequences for D-arms whereas trnE lacks the sequence for a T-arm. There is a stem-and-loop with a poly-T stretch in the loop in the control regions of both mt chromosomes (Figure 5); this may contain the sites of initiation of replication and transcription. There are two putative pseudogenes in mt chromosome I: P-nad4 (IV, 216 bp) and P-nad5 (III, 207 bp); and two putative pseudogenes in mt chromosome II: P-cox3 (I, 322 bp) and P-nad5 (II, 108 bp) (Figure 1 and Figure S2). These putative pseudogenes have identical or near-identical sequences to parts of their full-length counterparts. The A+T content of mt chromosome I and mt chromosome II were 67.78% and 69.54%, respectively. The nucleotide composition, AT-skew, and GC-skew between the two chromosomes and among the genes were summarized in Table 2, Table S2, and Table S3. The codon usages for the 13 mt protein-coding genes of L. bostrychophila were summarized in Table S4.


The multipartite mitochondrial genome of Liposcelis bostrychophila: insights into the evolution of mitochondrial genomes in bilateral animals.

Wei DD, Shao R, Yuan ML, Dou W, Barker SC, Wang JJ - PLoS ONE (2012)

Putative secondary structures of the 20 tRNA genes identified in the mitochondrial genome of Liposcelis bostrychophila.Bars indicate Watson-Crick base pairings, and dots between G and U pairs mark canonical base pairings appearing in RNA.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3316519&req=5

pone-0033973-g004: Putative secondary structures of the 20 tRNA genes identified in the mitochondrial genome of Liposcelis bostrychophila.Bars indicate Watson-Crick base pairings, and dots between G and U pairs mark canonical base pairings appearing in RNA.
Mentions: Sixteen of the 20 tRNA genes in the Beibei strain of L. bostrychophila have the conventional clover-leaf secondary structures (Figure 4). Three tRNA genes, trnR, trnC and trnS1, lack the sequences for D-arms whereas trnE lacks the sequence for a T-arm. There is a stem-and-loop with a poly-T stretch in the loop in the control regions of both mt chromosomes (Figure 5); this may contain the sites of initiation of replication and transcription. There are two putative pseudogenes in mt chromosome I: P-nad4 (IV, 216 bp) and P-nad5 (III, 207 bp); and two putative pseudogenes in mt chromosome II: P-cox3 (I, 322 bp) and P-nad5 (II, 108 bp) (Figure 1 and Figure S2). These putative pseudogenes have identical or near-identical sequences to parts of their full-length counterparts. The A+T content of mt chromosome I and mt chromosome II were 67.78% and 69.54%, respectively. The nucleotide composition, AT-skew, and GC-skew between the two chromosomes and among the genes were summarized in Table 2, Table S2, and Table S3. The codon usages for the 13 mt protein-coding genes of L. bostrychophila were summarized in Table S4.

Bottom Line: Intriguingly, mt chromosome I is twice as abundant as chromosome II.It appears that the selection pressure for compact mt genomes in bilateral animals favors small mt chromosomes when small mt chromosomes co-exist with the typical large mt chromosomes.Thus, small mt chromosomes may have selective advantages over large mt chromosomes in bilateral animals.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China.

ABSTRACT
Booklice (order Psocoptera) in the genus Liposcelis are major pests to stored grains worldwide and are closely related to parasitic lice (order Phthiraptera). We sequenced the mitochondrial (mt) genome of Liposcelis bostrychophila and found that the typical single mt chromosome of bilateral animals has fragmented into and been replaced by two medium-sized chromosomes in this booklouse; each of these chromosomes has about half of the genes of the typical mt chromosome of bilateral animals. These mt chromosomes are 8,530 bp (mt chromosome I) and 7,933 bp (mt chromosome II) in size. Intriguingly, mt chromosome I is twice as abundant as chromosome II. It appears that the selection pressure for compact mt genomes in bilateral animals favors small mt chromosomes when small mt chromosomes co-exist with the typical large mt chromosomes. Thus, small mt chromosomes may have selective advantages over large mt chromosomes in bilateral animals. Phylogenetic analyses of mt genome sequences of Psocodea (i.e. Psocoptera plus Phthiraptera) indicate that: 1) the order Psocoptera (booklice and barklice) is paraphyletic; and 2) the order Phthiraptera (the parasitic lice) is monophyletic. Within parasitic lice, however, the suborder Ischnocera is paraphyletic; this differs from the traditional view that each suborder of parasitic lice is monophyletic.

Show MeSH
Related in: MedlinePlus