Sexual Conflict Resolved by Invasion of a Novel Sex Determiner in Lake Malawi Cichlid Fishes

Roberts, Reade B.; Ser, Jennifer R.; Kocher, Thomas D.

doi:10.1126/science.1174705

Cited by 330 publications

(431 citation statements)

References 19 publications

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“…They showed that OB was presumably linked to a female heterogametic sex determiner (W), while a male heterogametic locus (Y) was observed on a different chromosome (Albertson, 2002). The segregation of (i) OB on linkage group 5 within multiple species of rock-dwelling Malawi cichlids (Roberts et al, 2009), as well as (ii) both sex-determining systems within species of the genus Metriaclima (Ser et al, 2010) has been confirmed using selective screening of color-and/or sex-associated markers. The study by Ser et al (2010) is particularly notable here because it demonstrated that some Metriaclima species segregate both XY and ZW sex systems and also speculated that other sex determiners must be present in the genomes of LM rock-dwelling cichlids.…”

Section: Introductionmentioning

confidence: 97%

Genetic interactions controlling sex and color establish the potential for sexual conflict in Lake Malawi cichlid fishes

Parnell

Streelman

2012

Heredity

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Sex-determining systems may evolve rapidly and contribute to lineage diversification. In fact, recent work has suggested an integral role of sex chromosome evolution in models of speciation. We use quantitative trait loci analysis of restriction site-associated DNA -tag single nucleotide polymorphisms to identify multiple loci responsible for sex determination and reproductively adaptive color phenotypes in Lake Malawi cichlids. We detect a complex epistatic sex system consisting of a major female heterogametic ZW locus on chromosome 5, two separate male heterogametic XY loci on chromosome 7, and two additional interacting loci on chromosomes 3 and 20. Our data support the known chromosomal linkage between orange blotch color and ZW, as well as novel genetic associations between male blue nuptial color and two sex determining regions (an XY and ZW locus). These results provide further empirical evidence for a complex antagonistic sex-color system in this species flock and suggest a possible role for, and effect of, polygenic sex-determining systems in rapid evolutionary diversification.

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Section: Introductionmentioning

confidence: 97%

Genetic interactions controlling sex and color establish the potential for sexual conflict in Lake Malawi cichlid fishes

Parnell

Streelman

2012

Heredity

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“…Numerous studies regarding theoretical considerations on sexual conflict and sex chromosomes sharply contrast with a very limited empirical evidence for the existence of sexually antagonistic loci. Among few well-documented cases are genes increasing male reproductive success but affecting survival, such as those encoding coloration in guppies and Lake Malawi cichlids (Lindholm and Breden, 2002;Roberts et al, 2009). However, virtually nothing is known about sexually antagonistic effects caused by genes with sex differences in development.…”

Section: Evolutionary Persistence Of a Short Sdrmentioning

confidence: 99%

The sex locus is tightly linked to factors conferring sex-specific lethal effects in the mosquito Aedes aegypti

et al. 2016

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In many taxa, sex chromosomes are heteromorphic and largely non-recombining. Evolutionary models predict that spread of recombination suppression on the Y chromosome is fueled by the accumulation of sexually antagonistic alleles in close linkage to the sex determination region. However, empirical evidence for the existence of sexually antagonistic alleles is scarce. In the mosquito Aedes aegypti, the sex-determining chromosomes are homomorphic. The region of suppressed recombination, which surrounds the male-specific sex-determining gene, remains very small, despite ancient origin of the sex chromosomes in the Aedes lineage. We conducted a genetic analysis of the A. aegypti chromosome region tightly linked to the sex locus. We used a strain with an enhanced green fluorescent protein (EGFP)-tagged transgene inserted near the male-determining gene to monitor crossing-over events close to the boundary of the sex-determining region (SDR), and to trace the inheritance pattern of the transgene in relation to sex. In a series of crossing experiments involving individuals with a recombinant sex chromosome we found developmental abnormalities leading to 1:2 sex biases, caused by lethality of half of the male or female progeny. Our results suggest that various factors causing sex-specific lethal effects are clustered within the neighborhood of the SDR, which in the affected sex are likely lost or gained through recombination, leading to death. These may include genes that are recessive lethal, vital for development and/or sexually antagonistic. The sex chromosome fragment in question represents a fascinating test case for the analysis of processes that shape stable boundaries of a non-recombining region.

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“…Also for this gene an accelerated rate of protein evolution was determined (Terai et al 2002a). The Pax7 locus appears to be involved in the formation of the orange blotch phenotype (Roberts et al 2009). Finally, it has been shown that csf1ra is involved in the development of the colorful egg-spots on the male anal fin .…”

Section: Introductionmentioning

confidence: 99%

Molecular Characterization of Two Endothelin Pathways in East African Cichlid Fishes

Diepeveen

Salzburger

2011

J Mol Evol

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The adaptive radiations of cichlid fishes in East Africa have been associated with the acquisition of evolutionary novelties as well as the ecological opportunities existing in the East African Great lakes. Two remarkable evolutionary innovations are the pharyngeal jaw apparatus, found in all cichlid species, and the anal fin egg-spots of mouthbrooding cichlids. Based on their conserved functions during the development of both the jaw apparatus and pigmentation, the endothelin ligands and receptors form a putative link between these naturally and sexually selected traits. Here we study the evolutionary history of four members of two endothelin pathways (Edn1/EdnrAa and Edn3b/EdnrB1a) to elucidate their possible roles during the evolution and development of key innovations in East African cichlids species. The analyses performed on partial sequences (ca. 6,000 bp per taxon) show that all four endothelin family members evolved under purifying selection, although both ligands are characterized by an accelerated rate of protein evolution in comparison to the receptors. In accordance with earlier findings, we show that the mature protein sequence of Edn1 and Edn3 are highly conserved, also in cichlids, whereas the preproendothelin parts are variable indicating relaxed selective constraints. In the receptors, nonsynonymous substitutions were mainly found in the ligand-binding domains suggesting functional divergence. Gene expression assays with Real-Time PCR indeed reveal that the two studied endothelin pathways are expressed in the cichlid pharyngeal jaw and in the haplochromine egg-spot (among other pigment-cell containing tissues), suggesting their involvement during morphogenesis of naturally and sexually selected traits in cichlids.

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Sexual Conflict Resolved by Invasion of a Novel Sex Determiner in Lake Malawi Cichlid Fishes

Cited by 330 publications

References 19 publications

Genetic interactions controlling sex and color establish the potential for sexual conflict in Lake Malawi cichlid fishes

Genetic interactions controlling sex and color establish the potential for sexual conflict in Lake Malawi cichlid fishes

The sex locus is tightly linked to factors conferring sex-specific lethal effects in the mosquito Aedes aegypti

Molecular Characterization of Two Endothelin Pathways in East African Cichlid Fishes

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