Reproductive Success is Secured by a Rapidly-Evolving Short Peptide in Female Aedes Aegypti Mosquitoes

<p>The mosquito lineage spans hundreds of millions of years of evolution, and this period has honed the yellow fever mosquito, Aedes aegypti, into a precise and expert predator. While nectar and plant-derived carbohydrates are sufficient sources of nutrition to maintain energy and metabolism, female mosquitoes must acquire multiple ingredients to successfully reproduce and produce offspring. Healthy, motile sperm from a conspecific male and a complete blood meal from a human host are required for females to develop viable eggs, and thus ensure species survival. What are the internal mechanisms that coordinate the acquisition of these key elements with the maturation, ovulation, and fertilization of viable offspring? Aedes aegypti specifically is faced with a multitude of challenges, including climate unpredictability and reproductive interference by sympatric species to effect competitive displacement. These obstacles must be overcome to ensure successful reproduction. What are the molecular adaptations that have evolved in this unique species to guarantee inheritance of genetic material to the next generation? How can these processes be disrupted to sterilize this invasive vector of mosquito-borne disease? Here we show that two closely-linked, rapidly-evolving genes novel to the mosquito lineage, tweedledee and tweedledum, have time- and tissue-restricted expression in adult reproductive tissues in Aedes aegypti. We demonstrate that expression of these genes is localized to the mature ovarian follicular epithelium, female upper reproductive tract, an uncharacterized cell type in male accessory glands, and maturing sperm in the testes. With bioinformatic and syntenic analyses, we identify putative orthologs of tweedledee in Culicinae species and characterize their rapid divergence and evolutionary trajectory across this lineage. Using CRISPR-Cas9 mutagenesis to disrupt tweedledee and tweedledum in Aedes aegypti, we discover a striking and heritable reproductive defect specifically caused by loss of tweedledee in female mosquitoes, regardless of male genotype or environmental conditions necessary for egg laying. By dissecting and inspecting reproductive tissues and laid, mature eggs, we determined that this reproductive collapse in tweedledee mutant mosquitoes is caused by a significant defect in the rate of fertilization, the critical first step of embryogenesis. Thus, tweedledee is able to ensure successful fertilization solely through interactions between the mature oocyte and supporting, somatic tissues in the female reproductive system. Our work highlights the importance of rapidly-diverging and novel genes in regulating essential processes such as fertilization, and will be critical in identifying maternal molecular targets to disrupt mosquito fertility and curb the spread of mosquito-borne diseases worldwide.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Thesis

Year

2026

Author dc:creator

• Lakhiani, Priyanka

Contributors dc:contributor

• Leslie B. Vosshall

• rapid evolution
• reproductive adaption
• lineage-specific
• fertilization
• phylogenetics
• Life Sciences

Repository record dc:identifier

https://digitalcommons.rockefeller.edu/student_theses_and_dissertations/838

OAI identifier oai:identifier

oai:digitalcommons.rockefeller.edu:student_theses_and_dissertations-1842