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Embryonic and larval development in the Midas cichlid fish species flock (Amphilophus spp.): a new evo-devo model for the investigation of adaptive novelties and species differences.

Kratochwil CF, Sefton MM, Meyer A - BMC Dev. Biol. (2015)

Bottom Line: Key morphological differences between the embryos of Midas cichlids and other teleosts are highlighted and discussed, including the presence of adhesive glands and different early chromatophore patterns, as well as variation in developmental timing.In the past, the species flocks of the African Great Lakes have received the most attention from researchers, but some lineages of the 300-400 species of Central American lakes are fascinating model systems for adaptive radiation and rapid phenotypic evolution.The availability of genetic resources, their status as a model system for evolutionary research, and the possibility to perform functional experiments including transgenesis makes the Midas cichlid complex a very attractive model for evolutionary-developmental research.

View Article: PubMed Central - PubMed

Affiliation: Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Konstanz, Germany. claudius.kratochwil@uni-konstanz.de.

ABSTRACT

Background: Central American crater lake cichlid fish of the Midas species complex (Amphilophus spp.) are a model system for sympatric speciation and fast ecological diversification and specialization. Midas cichlids have been intensively analyzed from an ecological and morphological perspective. Genomic resources such as transcriptomic and genomic data sets, and a high-quality draft genome are available now. Many ecologically relevant species-specific traits and differences such as pigmentation and cranial morphology arise during development. Detailed descriptions of the early development of the Midas cichlid in particular, will help to investigate the ontogeny of species differences and adaptations.

Results: We describe the embryonic and larval development of the crater lake cichlid, Amphilophus xiloaensis, until seven days after fertilization. Similar to previous studies on teleost development, we describe six periods of embryogenesis - the zygote, cleavage, blastula, gastrula, segmentation, and post-hatching period. Furthermore, we define homologous stages to well-described teleost models such as medaka and zebrafish, as well as other cichlid species such as the Nile tilapia and the South American cichlid Cichlasoma dimerus. Key morphological differences between the embryos of Midas cichlids and other teleosts are highlighted and discussed, including the presence of adhesive glands and different early chromatophore patterns, as well as variation in developmental timing.

Conclusions: The developmental staging of the Midas cichlid will aid researchers in the comparative investigation of teleost ontogenies. It will facilitate comparative developmental biological studies of Neotropical and African cichlid fish in particular. In the past, the species flocks of the African Great Lakes have received the most attention from researchers, but some lineages of the 300-400 species of Central American lakes are fascinating model systems for adaptive radiation and rapid phenotypic evolution. The availability of genetic resources, their status as a model system for evolutionary research, and the possibility to perform functional experiments including transgenesis makes the Midas cichlid complex a very attractive model for evolutionary-developmental research.

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Embryos during late blastula and early gastrulation phases. (A) 128-cell stage (5 h); (B) early high stage (8 h); (C) late high stage (10 h); (D) sphere stage (14 h); (E) dome stage (15 h); (F) 15% epiboly (16 h); (G) 20% epiboly (18 h). (H) 30% epiboly (20 h). The position of the germ ring (gr in F-H) is indicated by the dashed lines. Abbreviations: b, blastodisc; bd, blastoderm; es, embryonic shield, ez, evacuation zone, gr, germ ring; ps, perivitelline space. Scale bar = 500 μm.
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Fig4: Embryos during late blastula and early gastrulation phases. (A) 128-cell stage (5 h); (B) early high stage (8 h); (C) late high stage (10 h); (D) sphere stage (14 h); (E) dome stage (15 h); (F) 15% epiboly (16 h); (G) 20% epiboly (18 h). (H) 30% epiboly (20 h). The position of the germ ring (gr in F-H) is indicated by the dashed lines. Abbreviations: b, blastodisc; bd, blastoderm; es, embryonic shield, ez, evacuation zone, gr, germ ring; ps, perivitelline space. Scale bar = 500 μm.

Mentions: The blastula period extends from the 128-cell stage until gastrulation. Cleavages occur with increasing irregularity. The blastodisc acquires a more uniform appearance, and starts to thin and spread around the yolk (epiboly). At 50% epiboly, when half of the yolk is covered by the blastodisc, gastrulation begins (Figure 4).Figure 4


Embryonic and larval development in the Midas cichlid fish species flock (Amphilophus spp.): a new evo-devo model for the investigation of adaptive novelties and species differences.

Kratochwil CF, Sefton MM, Meyer A - BMC Dev. Biol. (2015)

Embryos during late blastula and early gastrulation phases. (A) 128-cell stage (5 h); (B) early high stage (8 h); (C) late high stage (10 h); (D) sphere stage (14 h); (E) dome stage (15 h); (F) 15% epiboly (16 h); (G) 20% epiboly (18 h). (H) 30% epiboly (20 h). The position of the germ ring (gr in F-H) is indicated by the dashed lines. Abbreviations: b, blastodisc; bd, blastoderm; es, embryonic shield, ez, evacuation zone, gr, germ ring; ps, perivitelline space. Scale bar = 500 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4352272&req=5

Fig4: Embryos during late blastula and early gastrulation phases. (A) 128-cell stage (5 h); (B) early high stage (8 h); (C) late high stage (10 h); (D) sphere stage (14 h); (E) dome stage (15 h); (F) 15% epiboly (16 h); (G) 20% epiboly (18 h). (H) 30% epiboly (20 h). The position of the germ ring (gr in F-H) is indicated by the dashed lines. Abbreviations: b, blastodisc; bd, blastoderm; es, embryonic shield, ez, evacuation zone, gr, germ ring; ps, perivitelline space. Scale bar = 500 μm.
Mentions: The blastula period extends from the 128-cell stage until gastrulation. Cleavages occur with increasing irregularity. The blastodisc acquires a more uniform appearance, and starts to thin and spread around the yolk (epiboly). At 50% epiboly, when half of the yolk is covered by the blastodisc, gastrulation begins (Figure 4).Figure 4

Bottom Line: Key morphological differences between the embryos of Midas cichlids and other teleosts are highlighted and discussed, including the presence of adhesive glands and different early chromatophore patterns, as well as variation in developmental timing.In the past, the species flocks of the African Great Lakes have received the most attention from researchers, but some lineages of the 300-400 species of Central American lakes are fascinating model systems for adaptive radiation and rapid phenotypic evolution.The availability of genetic resources, their status as a model system for evolutionary research, and the possibility to perform functional experiments including transgenesis makes the Midas cichlid complex a very attractive model for evolutionary-developmental research.

View Article: PubMed Central - PubMed

Affiliation: Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Konstanz, Germany. claudius.kratochwil@uni-konstanz.de.

ABSTRACT

Background: Central American crater lake cichlid fish of the Midas species complex (Amphilophus spp.) are a model system for sympatric speciation and fast ecological diversification and specialization. Midas cichlids have been intensively analyzed from an ecological and morphological perspective. Genomic resources such as transcriptomic and genomic data sets, and a high-quality draft genome are available now. Many ecologically relevant species-specific traits and differences such as pigmentation and cranial morphology arise during development. Detailed descriptions of the early development of the Midas cichlid in particular, will help to investigate the ontogeny of species differences and adaptations.

Results: We describe the embryonic and larval development of the crater lake cichlid, Amphilophus xiloaensis, until seven days after fertilization. Similar to previous studies on teleost development, we describe six periods of embryogenesis - the zygote, cleavage, blastula, gastrula, segmentation, and post-hatching period. Furthermore, we define homologous stages to well-described teleost models such as medaka and zebrafish, as well as other cichlid species such as the Nile tilapia and the South American cichlid Cichlasoma dimerus. Key morphological differences between the embryos of Midas cichlids and other teleosts are highlighted and discussed, including the presence of adhesive glands and different early chromatophore patterns, as well as variation in developmental timing.

Conclusions: The developmental staging of the Midas cichlid will aid researchers in the comparative investigation of teleost ontogenies. It will facilitate comparative developmental biological studies of Neotropical and African cichlid fish in particular. In the past, the species flocks of the African Great Lakes have received the most attention from researchers, but some lineages of the 300-400 species of Central American lakes are fascinating model systems for adaptive radiation and rapid phenotypic evolution. The availability of genetic resources, their status as a model system for evolutionary research, and the possibility to perform functional experiments including transgenesis makes the Midas cichlid complex a very attractive model for evolutionary-developmental research.

Show MeSH