+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Comparative transcriptomics of anal fin pigmentation patterns in cichlid fishes

Comparative transcriptomics of anal fin pigmentation patterns in cichlid fishes

Bmc Genomics 17: 712

Understanding the genetic basis of novel traits is a central topic in evolutionary biology. Two novel pigmentation phenotypes, egg-spots and blotches, emerged during the rapid diversification of East African cichlid fishes. Egg-spots are circular pigmentation markings on the anal fins of hundreds of derived haplochromine cichlids species, whereas blotches are patches of conspicuous anal fin pigmentation with ill-defined boundaries that occur in few species that belong to basal cichlid lineages. Both traits play an important role in the breeding behavior of this group of fishes. Knowledge about the origin, homology and underlying genetics of these pigmentation traits is sparse. Here, we present a comparative transcriptomic and differential gene expression analysis of egg-spots and blotches. We first conducted an RNA sequencing experiment where we compared egg-spot tissue with the remaining portion of egg-spot-free fin tissue using six individuals of Astatotilapia burtoni. We identified 1229 differentially expressed genes between the two tissue types. We then showed that rates of evolution of these genes are higher than average estimated on whole transcriptome data. Using quantitative real-time PCR, we found that 29 out of a subset of 46 differentially expressed genes showed an analogous expression pattern in another haplochromine species' egg-spots, Cynotilapia pulpican, strongly suggesting that these genes are involved in the egg-spot phenotype. Among these are the previously identified egg-spot gene fhl2a, two known patterning genes (hoxC12a and bmp3) as well as other pigmentation related genes such as asip. Finally, we analyzed the expression patterns of the same gene subset in two species that feature blotches instead of egg-spots, one haplochromine species (Pseudocrenilabrus philander) and one ectodine species (Callochromis macrops), revealing that the expression patterns in blotches and egg-spots are rather distinct. We identified several candidate genes that will serve as an important and useful resource for future research on the emergence and diversification of cichlid fishes' egg-spots. Only a limited degree of conservation of gene expression patterns was detected between the egg-spots of the derived haplochromines and blotches from ancestral haplochromines, as well as between the two types of blotches, suggesting an independent origin of these traits.

Please choose payment method:

(PDF emailed within 0-6 h: $19.90)

Accession: 057459857

Download citation: RISBibTeXText

PMID: 27600936

DOI: 10.1186/s12864-016-3046-y

Related references

Comparative transcriptomics of Eastern African cichlid fishes shows signs of positive selection and a large contribution of untranslated regions to genetic diversity. Genome Biology and Evolution 3: 443-455, 2011

Complete mitochondrial DNA sequences of the threadfin cichlid (Petrochromis trewavasae) and the blunthead cichlid (Tropheus moorii) and patterns of mitochondrial genome evolution in cichlid fishes. Plos One 8(6): E67048, 2014

The evolution of genes for pigmentation in African cichlid fishes. Gene 343(2): 337-346, 2004

Genetic basis of continuous variation in the levels and modular inheritance of pigmentation in cichlid fishes. Molecular Ecology 23(21): 5135-5150, 2014

A small number of genes underlie male pigmentation traits in Lake Malawi cichlid fishes. Journal of Experimental Zoology. Part B, Molecular and Developmental Evolution 318(3): 199-208, 2012

Anal fin pigmentation in Brachyrhaphis fishes is not used for sexual mimicry. Plos One 13(3): E0194121, 2018

Relationships between spot type on male anal fin of Malawian mouth-brooding cichlid fishes and mating behavior. Journal of the Faculty of Applied Biological Science Hiroshima University 40: 27-32, 2001

Transcriptomics and comparative analysis of three antarctic notothenioid fishes. Plos One 7(8): E43762, 2013

Genomics of Adaptation to Multiple Concurrent Stresses: Insights from Comparative Transcriptomics of a Cichlid Fish from One of Earth's Most Extreme Environments, the Hypersaline Soda Lake Magadi in Kenya, East Africa. Journal of Molecular Evolution 81(3-4): 90-109, 2016

Patterns of sexual size dimorphism in African cichlid fishes. South African Journal of Science 93(11-12): 498-508, 1997

Comparative osteology and relationships of neotropical cichlid fishes. Diss. Int: 2488B-2489B., 1971

Cichlid fishes as models of ecological diversification: patterns, mechanisms, and consequences. Hydrobiologia 748(1): 7-27, 2015

Sexual selection determines parental care patterns in cichlid fishes. Evolution; International Journal of Organic Evolution 62(8): 2015-2026, 2008

Comparative chromosome mapping of repetitive DNAs in cichlid fishes. 2007

A comparative study of the soluble proteins of the eye lens of some cichlid fishes. Belgian Journal of Botany 125(2): 319-320, 1992