Open Access Research article

Demasculinization of the Anopheles gambiae X chromosome

Kalle Magnusson1, Gareth J Lycett2, Antonio M Mendes1, Amy Lynd2, Philippos-Aris Papathanos13, Andrea Crisanti1 and Nikolai Windbichler1*

Author Affiliations

1 Imperial College London, Department of Life Sciences, Imperial College Road, London, SW7 2AZ, UK

2 Liverpool School of Tropical Medicine, Pembroke Place, London, L3 5QA, UK

3 Division of Biology; California Institute of Technology, Pasadena, CA, USA

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BMC Evolutionary Biology 2012, 12:69  doi:10.1186/1471-2148-12-69

Published: 18 May 2012

Additional files

Additional file 1 :

Table S1. Subset of genes derived from the meta-analysis dataset that were classified as male- or female-biased in a statistically stringent manner.

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Additional file 2 :

Figure S1. Reporter gene expression in pupal testes dissected from A. gambiae transgenic lines that are heterozygous (autosomal) and hemizygous (X-linked) for the α-tubeGFP transgene. Transmission (left), fluorescence (middle) and merged (right) microphotographs showing the extent of eGFP expression in testes dissected from heterozygous α-tubulin-EGFP 3 L (top row) and hemizygous α-tubulin-EGFP X lines. Letters denote regions of the testes containing the following spermatogenic stages as described in [35]: H – hub, P - .Primary Spermatocytes, S – Secondary Spermatocytes, Sd – Spermatids, and Sp – Spermatozoa; Scale bar, 50 μm. Fluorescent images were taken with identical camera settings, except to allow visualization of very weak fluorescence in testes from the X linked lines, the exposure time was increased 10 fold to 100 ms (at 10 ms no fluorescence was observed).

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Additional file 3 :

Figure S2. Evolution of X-linked and autosomal sex-biased orthologs. Percentages of male- (blue) and female-biased (pink) orthologous genes identified when comparing the genomes of A. gambiae (An) with A. aegypti (Ae), C. quinquefasciatus (Cu) and D. melanogaster (Dm) are presented for X-linked (upper panels) and autosomal genes (lower panels). Statistically significant differences were evaluated by hypergeometric distribution using as reference the fraction of orthologous genes found in all X-linked or autosomal genes studied (P < 0.05, one asterisk; P < 0.01, two asterisks).

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Additional file 4 :

Table S2. Levels of codon bias for X-linked and autosomal sex-biased genes in A. gambiae. N indicates number of genes; Length indicates the mean number of base pair nucleotides for each category; ENC indicates the mean effective number of codons for each category; Fop indicates the mean frequency of optimal codons for each category. P-value for Mann-Whitney two-sample tests comparing values for male or female biased genes to the total number of genes in each category are present within brackets.

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Additional file 5 :

Figure S3. Duplication events in sex-biased genes of adult A. gambiae mosquitoes. A) Percentages of male- (blue) and female- biased (pink) genes located on the X chromosome or the autosomes of A. gambiae mosquitoes that were separated by a duplication event and present at least one paralogous sequence. Statistically significant differences were evaluated by hypergeometric distribution using as reference (grey) the percentages of genes found within the set of all X-linked or autosomal genes studied (P < 0.05, one asterisk; P < 0.01, two asterisks) B) Average number of duplication events and paralog sequences presented by male and female-biased genes. Statistical differences were evaluated by Mann–Whitney test against the observed events in all genes studies on either the X chromosome or in the autosomes.

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Additional file 6 :

Figure S4. Reporter gene expression of autosomal and X-linked transgenes in homozygous and hemizygous A. gambiae. Transmission (upper panels) and fluorescent microphotographs (GFP middle panels, RFP lower panels) showing the expression activity of male (M) and female (F) pupae of the α-tubulin promoter α-tubulin-EGFP X, α-tubulin-EGFP 2 L and α-tubulin-EGFP 3R transgenic lines carrying either one or two copies of the α-tubulin-eGFP construct into either the X chromosome or on chromosomes 2 L/3R.

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Additional file 7 :

Table S3. Non redundant set of one to one orthologs between A. gambiae and D. melanogaster that was used as a basis for the codon bias analysis.

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