Geographic dimorphism of the wild silkworm, <i>Bombyx mandarina</i>, in the chromosome number and the occurrence of a retroposon-like insertion in the arylphorin gene

Nakamura, Takashi; Banno, Yutaka; Nakada, Tohru; Nho, Si Kab; Xu, Mengqiu; Ueda, Kyoichiro; Kawarabata, Takeshi; Kawaguchi, Yutaka; Koga, Katsumi

doi:10.1139/g99-072

Cited by 18 publications

(19 citation statements)

References 8 publications

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“…It should be noted that ChBm and B. mori have the same number of chromosomes per haploid genome. A geographical survey and early work on ribosomal gene structure of the two karyotypic forms of wild silkworms suggested that the separation between the two types occurred north of the Korean Strait [32,33] . One recent study on interspecific hybrids of B. mori and the JaBm revealed that the M-chromosome of JaBm corresponds to two chromosomes of B. mori [9] Because the two types of wild silkworms are difficult to distin (Figure 3).…”

Section: Discussionmentioning

confidence: 99%

Characterization of mitochondrial genome of Chinese wild mulberry silkworm, Bomyx mandarina (Lepidoptera: Bombycidae)

Pan

Xia

et al. 2008

SCI CHINA SER C

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The complete mitochondrial genome of Chinese Bombyx mandarina (ChBm) was determined. The circular genome is 15682 bp long, and contains a typical gene complement, order, and arrangement identical to that of Bombyx mori (B. mori) and Japanese Bombyx mandarina (JaBm) except for two additional tRNA-like structures: tRNA( Ser(TGA))-like and tRN( AIle(TAT))-like. All protein-coding sequences are initiated with a typical ATN codon except for the COI gene, which has a 4-bp TTAG putative initiator codon. Eleven of 13 protein-coding genes (PCGs) have a complete termination codon (all TAA), but the remaining two genes terminate with incomplete codons. All tRNAs have the typical clover-leaf structures of mitochondrial tRNAs, with the exception of tRNA( Ser(TGA))-like, with a four stem-and-loop structure. The length of the A+T-rich region of ChBm is 484 bp, shorter than those of JaBm (747 bp) and B. mori (494-499 bp). Phylogenetic analysis among B. mori, ChBm, JaBm, and Antheraea pernyi (Anpe) showed that B. mori is more closely related to ChBm than JaBm. The earliest divergence time estimate for B. mori-ChBm and B. mori-JaBm is about 1.08+/-0.18-1.41+/-0.24 and 1.53+/-0.20-2.01+/-0.26 Mya, respectively. ChBm and JaBm diverged around 1.11+/-0.16-1.45+/-0.21 Mya.

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Section: Discussionmentioning

confidence: 99%

Characterization of mitochondrial genome of Chinese wild mulberry silkworm, Bomyx mandarina (Lepidoptera: Bombycidae)

Pan

Xia

et al. 2008

SCI CHINA SER C

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“…Furthermore, higher mutation rates are predicted for the Z chromosomes or the autosomes compared with the W chromosome because more cell divisions are required for spermatogenesis compared with oogenesis. The nucleotide sequences of the autosomes of B. mori , however, show high similarity with those of B. mandarina (Kusuda et al ., 1986; Nakamura et al ., 1999; Rodakis & Lecanidou, 1992). Therefore, estimating the time of divergence of the two Bombyx species by comparing the nucleotide sequences of their autosomes or Z chromosomes is difficult.…”

Section: Discussionmentioning

confidence: 99%

Nested retrotransposons on the W chromosome of the wild silkworm Bombyx mandarina

Abe

Sugasaki

Terada

et al. 2002

Insect Molecular Biology

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The W chromosome of the silkworms Bombyx mori or B. mandarina is recombinationally isolated from the Z chromosome and the autosomes. We previously characterized a female-specific randomly amplified polymorphic DNA (RAPD), designated W-Yamato, derived from the W chromosome of the wild silkworm Bombyx mandarina. To further analyse the W chromosome of B. mandarina, we obtained a lambda phage clone that contains the W-Yamato RAPD sequence and sequenced the 16.7 kb DNA insert. We found that this DNA comprises a nested structure of at least seven elements: six retrotransposons and one transposable element-like sequence. The transposable element-like sequence is inserted into a micropia-like retrotransposon (Karate). The Karate and the non-long terminal repeat (non-LTR) retrotransposon BMC1 are inserted into a 412-like retrotransposon (Judo). Furthermore, this Judo, and two non-LTR retrotransposons (Kurosawa and Kendo) are inserted into a Pao-like retrotransposon (Yamato). These results indicate that the retrotransposons inserted into the W chromosome are not efficiently removed but accumulate gradually as strata without recombination.

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“…Bombyx mandarina Moore is presumed to be the wild ancestor of B. mori because fertile hybrid progeny are produced from a cross between these two species (Nakamura et al 1999). Bombyx mandarina inhabits China, Korea, Japan, and far eastern Russia and is independent of humans, whereas the domesticated B. mori can no longer survive in nature.…”

Section: Discussionmentioning

confidence: 99%

Aspergillus bombycis genotypes (RFLP) from silkworm cultivation

et al. 2003

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Eighteen isolates of Aspergillus bombycis from samples of dust, insect frass, and soil collected from eight silkworm rearing facilities in Japan, as well as single silkworm rearing facilities in Indonesia and Malaysia, were subjected to DNA fingerprinting. PstI digests of total genomic DNA from each isolate were probed using the pAF 28 repetitive sequence. Among 18 isolates analyzed, 7 distinct DNA fingerprint groups were identified, including GTAb-2 isolated from rearing facilities in four prefectures of Japan. Aspergillus bombycis isolates share several features in common with domesticated yellow-green aspergilli, the koji molds used in traditional Oriental food fermentations, including a loose and deep colony texture, smoothwalled stipes, and the absence of sclerotia. Although aflatoxin is unknown from koji molds, all isolates of A. bombycis produced B and G aflatoxins. Aflatoxin has been linked to increased virulence in Aspergillus disease of silkworms, and there should be strong selection for aflatoxin production among clonal populations of A. bombycis adapted to silkworm cultivation. A hypothesis is offered that A. bombycis isolates from silkworm cultivation represent highly adapted forms of yet to be discovered "wild" populations that may infect Bombyx mandarina.

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Geographic dimorphism of the wild silkworm, Bombyx mandarina, in the chromosome number and the occurrence of a retroposon-like insertion in the arylphorin gene

Cited by 18 publications

References 8 publications

Characterization of mitochondrial genome of Chinese wild mulberry silkworm, Bomyx mandarina (Lepidoptera: Bombycidae)

Characterization of mitochondrial genome of Chinese wild mulberry silkworm, Bomyx mandarina (Lepidoptera: Bombycidae)

Nested retrotransposons on the W chromosome of the wild silkworm Bombyx mandarina

Aspergillus bombycis genotypes (RFLP) from silkworm cultivation

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