File:Salamander- early development.jpg

Salamander- early development

Early development of Ensatina eschscholtzii, an amphibian with a large, yolky egg. Animal pole view of four live embryos from two different clutches.

(A, B) Two embryos in early cleavage stages; white arrowheads point to two of the three jelly coat layers.

(C) Uncleaved egg

(D) embryo at four cell stage.

Scale bars = 1.0 mm.

Original File name: Figure 2. http://www.evodevojournal.com/content/1/1/6/figure/F2 (text modified from original reference)

Abstract

"This species has one of the largest eggs known for an amphibian, with a mean ± SD diameter of 6 ± 0.43 mm (range 5.3-6.9; n = 17 eggs). Cleavage is meroblastic until approximately the 16-cell stage (fourth or fifth cleavage). At the beginning of gastrulation, the blastocoel roof is one cell thick, and the dorsal lip of the blastopore forms below the equator of the embryo. The ventral lip of the blastopore forms closer to the vegetal pole, and relatively little involution occurs during gastrulation. Cell migration is visible through the transparent blastocoel roof of the gastrula. At the end of gastrulation, a small archenteron spreading dorsally from the blastopore represents the relatively small and superficial area of the egg where early embryonic axis formation occurs. The resulting pattern is similar to the embryonic disk described for one species of anuran."

Reference

<pubmed>20849648</pubmed>| Evodevo.

Collazo and Keller EvoDevo 2010 1:6 doi:10.1186/2041-9139-1-6

© 2010 Collazo and Keller; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.