Developmental Biology (Bio 445)

Lecture Guide Chap 3 (Wolpert)

 

All Vertebrates ….

1.      have a similar ___________  _______________.

2.      likely have similar ______________________ _____________.

 

Phylotypic stage –

        ____________________________________________

        ____________________________________________

        ____________________________________________

        ____________________________________________

 

Mammalian eggs are ___________ and non-________________ and the embryo is nourished by _________________- in the ___________________ and ______________________, then through the _________________________.

 

Cleavage of the Zygote: First week of life.

 

 

Days 1-2: ( in the ___________________________________ )

 

        ____   -  _________ cell stage.

 

____________________ - cells from _________________ divisions.

 

_____________________ - ________________________________ ___________________________________ .

 

________________ - _____________________________________ _____________________________________________________ .

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Day3: (entering the ______________________ )

 

____________________ (L. morus, ______________) ____ - _______ blastomeres, _______________________________ .

 

 

Day 4-5: ( in the __________________)

 

___________________ - when a ________________________  (_______________________________ ) forms  within the ________________________.

 

______________________________ is lost at this stage.

 

______________________ (_______________________) – thin outer layer.

 

______________________ (______________________) - ________ _____________________ blastomeres that give rise to the ____________________.

 

 

 

Day 6:

 

____________________ attaches to the _____________________ at the ________________________ ___________________ (__________________________________) .

 

Differentiation of the trophoblast:

1.    ________________________________ - cellular component; source of cells for the ____________________ .

 

2.    _______________________________ - no distinct cell boundaries (_____________________ _________________).

 

 

 

 

The syncytiotrophoblast produces ______________________ (hCG).

 

This maintains the activity of the ___________________________.

Also the target for __________________________ tests.

 

 

 

 

Day 7:

 

_________________ - layer of cells on the _______________ facing the ________________________________ (aka _____________________ ________________________).

 

 

Axis specification/induction

 

Mouse - ________________________________________.

 

Xenopus –

 

        __________ entry point marks the ________________ pole.

       

        Anterior/posterior axis appears determined by ______________ ___________________.

 

These genes are setup in _________________ and expressed at defined ___________________ and ___________________.

 

_____________________ is an example of a _______________ __________________.

 

Signaling centers.

____________________ - first ______________ center, induces the formation of the next center, the ____________________.

 

_______________________ - Dorsal center, and also induces _________________ structures and portions of the ____________.

 

 

 

Handedness:

 

Outwardly, vertebrates are _________________________________, however, internally, there is _______________________________ .

 

Theory:

Asymmetry at the _____________________________ is converted to an asymmetry at the _____________________ and _______________ level.

 

______________________ - a master regulatory gene responsible for ___________________  in the primitive streak.  Also, induces _______________________ expression, which leads to mesoderm regulation. 

 

In mice, the __________ gene has been shown to specify handedness.

 

______________________________ - mirror- image ____________________________________________________ .

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Specification and patterning of the germ layers:

 

________ map – identification of which __________ give rise to

_______________________ in the embryo.

 

___________ map - ____________________________________ _________________________________________________ .

 

-         The fact that these maps are different  suggest that _____________ _________________ are required to generate many tissues in the embryo.

 

_________ - (________________), maternal gene which induces mesoderm and endoderm signals.

 

__________ - (TGF-b family), induces mesoderm.

 

 

___________________ genes – ( __________ derived), take over at mid-blastula stage.

 

_________ - (secreted), dorsalizes mesoderm.

 

_________ - (_______________) ventralizes mesoderm.