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College of Natural Resources and Environment (CNRE)

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Browsing College of Natural Resources and Environment (CNRE) by Subject "0608 Zoology"

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    Identification and analysis of a novel microsatellite marker within the growth hormone gene promoter of Colossoma macropomum (Characiformes: Characidae) detected by TAIL-PCR
    Jaser, Suhaila K. K.; Perazza, Caio A.; Favaro, Leia C. L.; Goto, Mariana A.; de Oliveira, Alzira M.; Hallerman, Eric M.; Hilsdorf, Alexandre W. S. (Wiley, 2021-02-16)
    While in all vertebrates, growth hormone (GH) promotes post-natal growth, in fishes it also affects such metabolic functions as foraging rate, digestion, osmoregulation, and reproduction. The promoter region of the GH gene is an important target for studies of mechanisms regulating its expression, and polymorphisms within the promoter have been associated with performance traits in fishes. We used Thermal Asymmetric Interlaced PCR (TAIL-PCR) to amplify and sequence the 5′-flanking regions of the Colossoma macropomum GH (cmGH) gene. Based on a sequence of 1,038 bp, we designed three specific nested primers (R-290, R-186 and R-26) which were used with shorter arbitrary degenerate primers to amplify the 5′ proximal region of the cmGH gene. We identified a tetranucleotide (ATCC)4 microsatellite motif in this region, exhibiting four alleles (118, 122, 126 and 130 bp) within the population study. Genotypes at this locus deviated significantly from Hardy–Weinberg expectations (p ≤.05) and showed a low level of polymorphism (polymorphic information content = 0.163). High homozygosity (FIS = 0.147) was observed in the overall population. The polymorphism at the microsatellite makes it an important candidate for association studies between the respective genotypes, growth rate and other traits in farmed populations. Such studies may contribute to future breeding programs using marker-assisted selection upon this aquaculturally important species.
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    Multispecies colour polymorphisms associated with contrasting microhabitats in two Mediterranean wrasse radiations
    Fark, Sarya N.; Gerber, Steve; Alonzo, Suzanne H.; Kindsvater, Holly K.; Meier, Joana I.; Seehausen, Ole (Wiley, 2022-03-18)
    Intraspecific colour polymorphisms (CPs) present unique opportunities to study fundamental evolutionary questions, such as the link between ecology and phenotype, mechanisms maintaining genetic diversity and their putative role in speciation. Wrasses are highly diverse in ecology and morphology and harbour a variety of colour-polymorphic species. In the Mediterranean Sea, wrasses of the tribe Labrini evolved two species radiations each harbouring several species with a brown and a green morph. The colour morphs occur in complete sympatry in mosaic habitats with rocky outcrops and Neptune grass patches. Morph-specific differences had not been characterized yet and the evolutionary forces maintaining them remained unknown. With genome-wide data for almost all Labrini species, we show that species with CPs are distributed across the phylogeny, but show evidence of hybridization. This suggests that the colour morphs are either ancient and have been lost repeatedly, that they have evolved repeatedly or have been shared via hybridization. Focusing on two polymorphic species, we find that each colour morph is more common in the microhabitat providing the best colour match and that the morphs exhibit additional behavioural and morphological differences further improving crypsis in their respective microhabitats. We find little evidence for genetic differentiation between the morphs in either species. Therefore, we propose that these colour morphs represent a multi-niche polymorphism as an adaptation to the highly heterogeneous habitat. Our study highlights how colour polymorphism (CP) can be advantageous in mosaic habitats and that Mediterranean wrasses are an ideal system to study trans-species polymorphisms, i.e. polymorphisms maintained across several species, in adaptive radiations.