Scientist: Research Projects: Zebrafish Mutation Database

bielak has reduction of mandibular and hyoid structures and absence or few ceratobranchials. abstract

boxer has a jaw that is not extended. There are pectoral fin and retinotectal defects. All arches are short, thick, and strongly reduced. abstract

chinless has a reduced head and lacks arch-derived structures of the jaw and head. Embryos lack the entire pharyngeal skeleton including Meckels cartilage and palatoquadrate of the mandibular arch; the hyosymplectic, ceratohyal, interhyal and basihyal of the hyoid arch; and the basibranchials and ceratobranchials in arches 3-7. abstract

flathead has loss of gills, reduction of anterior structures, reduction or absence of posterior structures, and ceratohyal extends posteriorly and dorsally. abstract

hoover has a phenotype similar to sturgeon. The first two branchial arches are reduced. The Meckel's cartilage is fused to the palatoquadrate. The mouth stays open. The ceratohyal is sometimes in two pieces. Small pieces of additional cartilage are located close to the basihyal. Posterior arches are not affected. abstract

lockjaw has a ventrally displaced mouth, loss of gills, reduced hyoid, absence of some branchial arches, and reduced neurocranium. abstract

First arch structures not as severely reduced as in sucker, but the second arch is affected to the same degree. In the first arch, the posterior pole of the palatoquadrate curves either medially or laterally. In the second arch, the ceratohyal cartilage is reduced to two small elements. In a few larvae, the ceratohyal is less reduced and retains an elongated shape, but points posteriorly instead of anteriorly. Additional small cartilaginous elements are located around the basihyal. All ceretobranchials are present but third and fourth arches are reduced in length. abstract

Phenotype is milder than in schmerle and sucker. In the first arch, the basihyal cartilage is irregularly shaped and contains more cells than in wild-type larve. Additional unidentified pieces of cartilage occur around the basihyal and caudal to the Meckel's cartilage. abstract

Within the first arch, the lower jaw (Meckel's cartilage) is severely reduced or absent. The upper jaw (palatoquadrate) is also affected, only the pterygoid process remaining. In the second arch, the dorsal part of the hyosymplectic is broader than in wild-type larvae, whereas the ceratohyal is reduced and fused to the basihyal. Additional unidentified plate-like cartilaginous elements ventral to the ceratohyal are present. Posterior pharyngeal arches (ceratobranchials) are present but third and fourth arches are reduced in length. The neurocranium is unaffected. The sucker phenotype is caused by a mutation in the endothelin-1 (et-1) gene. abstract

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