Vloga materinskih učinkov v evoluciji spolne dvoličnosti

Opis projekta:

Projekt MATES je zasnovan na izsledkih kvantitativno-genetskih raziskav z namenom, da odkrije mehanistične osnove SSD vrste N. cruentata. Predlagana raziskava bo preučila vlogo in obseg neposrednih genetskih, materinih genetskih in okoljskih učinkov na telesno velikost pri obeh spolih, opredelila materine lastnosti, ki vplivajo na materine učinke, ter natančno določila gene, povezane s telesno velikostjo samic, in materine lastnosti, ki vplivajo na velikost obeh spolov. MATES ima štiri cilje: (1) identifikacijo genov, ki določajo telesno velikost pajkov; (2) ovrednotiti naravo materinskih učinkov, ki pojasnjujejo variabilnost v velikosti, torej če prevladujejo materinski genetski ali materinski okoljski učinki; (3) identificirati reproduktivne lastnosti samice, ki so potencialni vir materinskih učinkov, kot sta npr. velikost ali kvaliteta jajčnih celic; in (4) opredeliti gene, ki nadzorujejo materinske učinke s pomočjo asociacijskih študij na celotnem genomu. Raziskovalni projekt bo tako poglobil naše razumevanje nastanka SSD in naravo dedovanja teh lastnosti. Projekt je zasnovan interdisciplinarno in združuje sodobne metode iz kvantitativne genetike, genomike, biokemije in razvojne biologije. Raziskovalna skupina združuje raznovrstne raziskovalce s specializiranim znanjem in raziskovalce s širino, kar zagotavlja teoretično in tehnično usposobljenost raziskovalne skupine in uspeh projekta.

MATES odstira nove poglede na mehanizme nastanka razlik v fenotipih obeh spolov. Ponuja nov pogled na klasičen problem, ki bo z inovativnim raziskovalnimi pristopi nemara odstrl pot alternativnim razlagam in postavil nov mejnik evolucijski biologiji.

Oddelek UP FAMNIT, v okviru katerega se izvaja projekt:

Oddelek za biodiverziteto

Description:

Phenotypic sex differences present a fascinating evolutionary puzzle, encapsulated by the notion of 'one genome, two sexes'. This highlights the enigma of divergent phenotypes arising from shared genomes. A key element in this complexity is sexual conflict, where genetic variants beneficial for one sex may be detrimental to the other. The genetic and molecular mechanisms that allow sex-specific evolution of sexually dimorphic traits remain largely unknown. Contemporary research points to the significant roles of differential gene expression and mRNA splicing. Moreover, recent advancements have led to a growing recognition of maternal effects, i.e. the causal influences of the maternal phenotype on the offspring phenotype other than that of directly transmitted genetic variants, as significant contributors to phenotypic variance. The maternal effects can be attributed, like for most traits, to the environmental conditions experienced by the mother or to the genes she carries. In cases where maternal genetic effects are present, they offer a heritable component to phenotypic variance. However, incorporating and quantifying the maternal genetic effects in evolutionary research is still an emerging and underexplored area.

The proposed project - MATES - is a logical continuation of our long-term research on extreme sexual size dimorphism (SSD) in the African hermit spider, Nephilingis cruentata, a species where females are on average 75 times larger than males. Applying advanced quantitative genetics, we found that female size variation is largely governed by direct genetic effects (~ 26%), whereas variation in male size is influenced to ~ 25% by maternal effects. The maternal effects account for only ~13% of the variation in female body size, whereas the impact of direct genetic effects on male body size is minimal. These results support a straightforward mechanism that avoids sexual conflict and explains how evolution is possible towards sex-specific optima of the same trait. This ground-breaking finding offers a new understanding of sexual conflict resolution in evolutionary biology and opens new pathways for exploring mechanisms enabling sexual dimorphism.

Expanding upon the recent insights gained from quantitative genetic approaches, the MATES is designed to reveal the mechanisms underlying body size differences between female and male N. cruentata. The research will investigate the impact of direct genetic, maternal genetic, and maternal environmental influences on body size in both sexes. It will focus on identifying genes that directly affect size, determining maternal traits exerting maternal genetic effects and detecting genetic variants underlying them. The MATES study has four key objectives: (1) Identifying genes candidate genes associated with adult size, (2) Quantifying the origins of maternal effects on offspring size, whether environmental, genetic, or both, (3) Identifying specific maternal traits like egg size or quality that may be origins of maternal effects, and (4) using Genome-Wide Association Studies to ultimately connect genetic variation of maternal traits with maternal genetic variation of offspring traits, enhancing our understanding of SSD and trait inheritance. The project proposes a comprehensive interdisciplinary approach, integrating various state-of-the-art approaches from quantitative genetics, genomics, biochemistry, and developmental biology. Our MATES team is committed to bringing together a diverse group of highly specialised experts and versatile generalists, each bringing unique skills to further the aims of our study.

The MATES challenges the current knowledge of mechanisms enabling phenotypic sex differences. It will contribute significantly to science by offering fresh perspectives and challenging existing theories in evolutionary biology. This pioneering research is expected to lead t o ground-breaking discoveries and set new benchmarks in evolutionary biology.