Friday, September 05, 2008

Zebrafish Embryos

Here are some pictures of zebrafish embryos I took at work over the past few days which illustrate the fast pace of their development.

The first pic shows a bunch of eggs only 24 hours post-fertilization. You can tell that each embryo is enclosed by a shell. You can tell that each embryo already has its basic plan well laid-out already: you can make out two eyes, a tail, etc. The spherical ball in the center is called the yolk sac, which helps deliver nutrients to the growing fish.

Here's a close-up of on of the embryos.
By 48 hours, some of the fish will have "hatched" (that is, come out of their shell), and those which have not hatched you can easily help them by stripping off the shell with a pair of forceps. Shortly afterwards the body axis will straighten out. The yolk sac is still attached but now lengthened out.Mmmmmm...doesn't that just make you hungry for a nice, juicy salmon?