A life table provides data on the number of individuals alive in different age classes and the age-specific survival or mortality rates in these age classes.

TLS Online TPP Program

#Id: 7159

#Unit 5. Developmental Biology

Amphibian Gastrulation

TLS Online TPP Program

#Id: 7160

#Unit 5. Developmental Biology

Epiboly: The thinning and spreading of the animal cap cells over the vegetal hemisphere, powered by proliferation and radial intercalation. is critical for activating the genes that specify cells to be endoderm. Thus, the fate of the vegetal cells is to become endodermal

TLS Online TPP Program

#Id: 7161

#Unit 5. Developmental Biology

The mechanism for “bottom-up” specification of germ layers of the frog embryo resides in a set of mRNAs that are tethered to the vegetal cortex

TLS Online TPP Program

#Id: 7162

#Unit 5. Developmental Biology

TLS Online TPP Program

#Id: 7163

#Unit 5. Developmental Biology

The mRNA for the transcription factor VegT, which becomes apportioned to the vegetal cells during cleavage. VegT is critical in generating both the endodermal and mesodermal lineages.

TLS Online TPP Program

#Id: 7164

#Unit 5. Developmental Biology

One of the genes activated by VegT protein encodes the Sox17 transcription factor.