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bioRxiv · 10.1101/690370

The Drosophila fertility factor kl-3 is linked to the Y-chromosome of the vector of Chagas’ disease Triatoma infestans (Hemiptera: Reduviidae) and is essential for male fertility

Martins, C. H.·Silva, R. S. V. P.·Ferreira, T. K.·Paim, R.·Pessoa, G. C. D.·Sant'Anna, M. V.·Araujo, R. N.·Gontijo, N. F.·Pereira, M. H.·Carvalho, A. B.·KOERICH, L.
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Abstract

In many insects, the Y chromosome plays a key role in sexual determination and male fertility. The Chagas disease vector Triatoma infestans has 22 autosomal chromosomes and a pair of XY sex chromosomes. However, the knowledge on the Y chromosome of this species, its genetic content or its biological function, is very poor. Due to repetitive DNA, Y chromosome sequences are poorly assembled in genome projects, hindering structural and functional studies on Y-linked genes. Our group has developed many of the bioinformatic tools to identify Y-linked sequences in assembled genomes. Here, we describe the identification of a {gamma}-dynein heavy chain linked to the Y-chromosome of T. infestans. This protein is orthologous to the Drosophila melanogaster Y-linked gene kl-3. In D. melanogaster, dyneins of the Y chromosome are known as male fertility factors and their deletion causes male infertility. We performed knockdown of the kl-3 expression to ascertain its function in T. infestans. Our results showed that injection of dsKL3 reduced, significantly, the fertility of T. infestans males (p<0.01). The mean number of eggs laid by the control group was 35.64 eggs/couple while the kl-3 knockdown group was of 11.82 eggs/couple (five couples did not lay any eggs). Differences in eclosion rate was even more significant, with a hatching mean rate of 16.85{+/-}10.03 and 1.69{+/-}3.58 (p<0.001) for the control and the silenced groups respectively. Our results suggest that kl-3 maintains its functional role as essential for male fertility in T. infestans. Hence, it seems that the Y-chromosome of T. infestans has a key role in male fertility. This is the first report of a kl-3 orthologue linked to the Y chromosome of an insect species outside the diptera clade. In addition to the first report of a Y-linked gene in T. infestans with a role for male fertility, this finding is of great relevance for the study of the evolution of Y chromosomes and further studies that could lead to novel approaches in insect control.

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Martins, C. H., Silva, R. S. V. P., Ferreira, T. K., Paim, R., Pessoa, G. C. D., Sant'Anna, M. V., Araujo, R. N., Gontijo, N. F., Pereira, M. H., Carvalho, A. B., KOERICH, L.. 2019-07-02. The Drosophila fertility factor kl-3 is linked to the Y-chromosome of the vector of Chagas’ disease Triatoma infestans (Hemiptera: Reduviidae) and is essential for male fertility. https://doi.org/10.1101/690370

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