Embryonic development of the self‐fertilizing mangrove killifish Kryptolebias marmoratus

Abstract

The mangrove killifish, Kryptolebias marmoratus, is a self-fertilizing vertebrate offering vast potential as a model species in many biological disciplines. Previous studies have defined developmental stages but lacked visual representations of the various embryonic structures. We offer detailed photographic images of K. marmoratus development with revised descriptions. An improved dechorionation method was developed to provide high resolution photographs, in addition to a microinjection technique enabling cell marking in the yolk syncytial layer. Embryos were also treated with PTU (1-phenyl 2-thiourea), an inhibitor of melanogenesis, to provide optical transparency revealing internal structures in late stages of development. Chemical exposures (PTU and retinoic acid) demonstrated that K. marmoratus embryos were sensitive to chemicals, illustrating further their usefulness in developmental biology studies. Our data suggest that K. marmoratus embryos are easily used and manipulated, supporting the use of this hermaphroditic vertebrate as a strong comparative model system in embryology, evolution, genetics, environmental and medical biology. Developmental Dynamics 240:1694-1704,

Bmp Suppression in Mangrove Killifish Embryos Causes a Split in the Body Axis

“…A phenotype resembling snailhouse was observed in K. marmoratus by exposing embryos to DM from the late blastula stage (Figure 1C) (see [18] for K. marmoratus developmental stages), displaying a shortened and curled tail (Figure 1 C3 arrowhead) by 3 days post-fertilization (dpf). Embryos treated with the same concentration but starting from late epiboly (Figure 1D) produced a milder phenotype characterised by its bent tail (Figure 1 D3 arrowhead).…”

“…Consequently the ratio between the diameter of the blastoderm margin and the yolk is 1∶1.4 for killifish Stage 10 embryos and 1∶1 in zebrafish embryos at an equivalent stage (shield stage) [18], [21]. As the blastoderm is under extreme tension to move over the yolk during epiboly, the larger yolk of K. marmoratus embryos may increase the stretch required for the sheet of deep cells to reach the mid-gastrula point, which may enhance the epiboly defect less obvious in zebrafish.…”

“…Both control and DM treated embryos were reared under the same conditions as adult individuals. Embryonic stages were determined using the staging series in [18]. All Protocol used were permitted by the UK Home Office guidance to Animals Scientific Procedures Act (Project License No.…”

“…Imaging of live and fixed K. marmoratus embryos was performed using the Agarose bed and methyl cellulose techniques respectively, described in detail by [18], [19].…”

“…The self-fertilizing ability of mangrove killifish makes this species very interesting for mutant screening as zygotic mutant phenotypes appear in F2 embryos, one generation earlier than other animals such as zebrafish and medaka [17]. To establish the species as a novel model for developmental biology, we have recently analysed developmental stages and also developed basic embryological techniques for gene expression, cell labelling, imaging, and chemical treatment [18], [19]. However, the role of key signalling pathways during early development in K. marmoratus has not yet been investigated.…”