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Chen C, Compton A, Nikolouli K, Wang A, Aryan A, Sharma A, Qi Y, Dellinger C, Hempel M, Potters M, Augustinos A, Severson DW, Bourtzis K, Tu Z. Marker-assisted mapping enables forward genetic analysis in Aedes aegypti, an arboviral vector with vast recombination deserts. Genetics 2022; 222:iyac140. [PMID: 36083009 PMCID: PMC9630976 DOI: 10.1093/genetics/iyac140] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 08/29/2022] [Indexed: 11/14/2022] Open
Abstract
Aedes aegypti is a major vector of arboviruses that cause dengue, chikungunya, yellow fever, and Zika. Although recent success in reverse genetics has facilitated rapid progress in basic and applied research, integration of forward genetics with modern technologies remains challenging in this important species, as up to 47% of its chromosome is refractory to genetic mapping due to extremely low rate of recombination. Here, we report the development of a marker-assisted mapping strategy to readily screen for and genotype only the rare but informative recombinants, drastically increasing both the resolution and signal-to-noise ratio. Using marker-assisted mapping, we mapped a transgene that was inserted in a >100-Mb recombination desert and a sex-linked spontaneous red-eye (re) mutation just outside the region. We subsequently determined, by CRISPR/Cas9-mediated knockout, that cardinal is the causal gene of re, which is the first forward genetic identification of a causal gene in Ae. aegypti. The identification of the causal gene of the sex-linked re mutation provides the molecular foundation for using gene editing to develop versatile and stable genetic sexing methods. To facilitate genome-wide forward genetics in Ae. aegypti, we generated and compiled a number of lines with markers throughout the genome. Thus, by overcoming the challenges presented by the vast recombination deserts and the scarcity of markers, we have shown that effective forward genetic analysis is increasingly feasible in this important arboviral vector species.
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Affiliation(s)
- Chujia Chen
- Genetics Bioinformatics and Computational Biology Program, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Austin Compton
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Katerina Nikolouli
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, IAEA Laboratories, 2444 Seibersdorf, Austria
| | - Aihua Wang
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Azadeh Aryan
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Atashi Sharma
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Yumin Qi
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Camden Dellinger
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Melanie Hempel
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Mark Potters
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Antonios Augustinos
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, IAEA Laboratories, 2444 Seibersdorf, Austria
| | - David W Severson
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Kostas Bourtzis
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, IAEA Laboratories, 2444 Seibersdorf, Austria
| | - Zhijian Tu
- Genetics Bioinformatics and Computational Biology Program, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
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Misbah-ul-Haq M, Augustinos AA, Carvalho DO, Duran de la Fuente L, Bourtzis K. The Effect of an Irradiation-Induced Recombination Suppressing Inversion on the Genetic Stability and Biological Quality of a White Eye-Based Aedes aegypti Genetic Sexing Strain. Insects 2022; 13:946. [PMID: 36292893 PMCID: PMC9604213 DOI: 10.3390/insects13100946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 09/28/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
Aedes aegypti is the primary vector of diseases such as dengue, chikungunya, Zika fever, and yellow fever. The sterile insect technique (SIT) has been proposed as a species-specific and environment-friendly tool for the suppression of mosquito vector populations as a major component of integrated vector management strategies. As female mosquitoes are blood-feeders and may transmit pathogenic microorganisms, mosquito SIT depends on the release of sterile males. Genetic sexing strains (GSS) can be used for the efficient and robust separation of males from females. Two Ae. aegypti GSS were recently developed by exploiting eye colour mutations, resulting in the Red-eye GSS (RGSS) and the White-eye GSS (WGSS). In this study, we compared two WGSS, with and without the chromosomal inversion 35 (Inv35), and evaluated their biological quality, including genetic stability. Our results suggest that the WGSS/Inv35 presents a low recombination rate and long-term genetic stability when recombinants are removed from the colony (filtering) and a slow accumulation of recombinants when they are not removed from the colony (non-filtering). The two strains were similar with respect to fecundity, pupal and adult recovery rates, pupation curve, and pupal weight. However, differences were detected in fertility, survival rate of females, and flight ability of males. The WGSS/Inv35 presented lower fertility, higher survival rate of females, and better flight ability of males compared to the WGSS.
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Affiliation(s)
- Muhammad Misbah-ul-Haq
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, 2444 Seibersdorf, Austria
- Nuclear Institute for Food and Agriculture, Peshawar 446, Pakistan
| | - Antonios A. Augustinos
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, 2444 Seibersdorf, Austria
| | - Danilo O. Carvalho
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, 2444 Seibersdorf, Austria
| | - Lucia Duran de la Fuente
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, 2444 Seibersdorf, Austria
| | - Kostas Bourtzis
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, 2444 Seibersdorf, Austria
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Misbah-ul-Haq M, Carvalho DO, Duran De La Fuente L, Augustinos AA, Bourtzis K. Genetic Stability and Fitness of Aedes aegypti Red-Eye Genetic Sexing Strains With Pakistani Genomic Background for Sterile Insect Technique Applications. Front Bioeng Biotechnol 2022; 10:871703. [PMID: 35433649 PMCID: PMC9009520 DOI: 10.3389/fbioe.2022.871703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 03/14/2022] [Indexed: 11/30/2022] Open
Abstract
The mosquito species Aedes aegypti is the primary transmitter of viruses that cause endemic diseases like dengue in Pakistan. It is also a cause of other vector-borne diseases like yellow fever, Zika fever, and chikungunya, which significantly impact human health worldwide. In the absence of efficient vaccines (except for yellow fever) or drugs, vector control methods, such as the sterile insect technique (SIT), have been proposed as additional tools for the management of these diseases. Mosquito SIT programs are based on the release of sterile males and it is important female releases to be ideally zero or to be kept at a minimum, since females are the ones that bite, blood-feed and transmit pathogens. Recently, an Ae. aegypti genetic sexing strain (GSS), with and without a recombination-suppressing inversion (Inv35), was developed using the eye color as a selectable marker, with males having black eyes and females red eyes. In the present study, we introgressed the sexing features and the Inv35 of the Ae. aegypti red-eye GSS into the Pakistani genomic background aiming to their future use for SIT applications in the country. Both introgressed strains, the Red-eye GSS-PAK and the Red-eye GSS/Inv35-PAK, were evaluated in respect to their genetic stability and biological quality by assessing parameters like recombination rate, fecundity, fertility, pupal and adult recovery, time of development, pupal weight, survival, and flight ability in comparison with a wild Pakistani population (PAK). The results suggest that the sexing features and the recombination suppression properties of Inv35 were not affected after their introgression into the local genomic background; however, some biological traits of the two newly constructed strains were affected, positively or negatively, suggesting that a thorough quality control analysis should be performed after the introgression of a GSS into a new genomic background prior to its use in SIT field trials or applications. The importance of using GSS with local genomic background for SIT applications against Aedes aegypti is also discussed.
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Affiliation(s)
- Muhammad Misbah-ul-Haq
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Seibersdorf, Austria
- Nuclear Institute for Food and Agriculture, Peshawar, Pakistan
- *Correspondence: Muhammad Misbah-ul-Haq, ; Kostas Bourtzis,
| | - Danilo O. Carvalho
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Seibersdorf, Austria
| | - Lucia Duran De La Fuente
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Seibersdorf, Austria
| | - Antonios A. Augustinos
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Seibersdorf, Austria
| | - Kostas Bourtzis
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Seibersdorf, Austria
- *Correspondence: Muhammad Misbah-ul-Haq, ; Kostas Bourtzis,
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