Cell Fates

Question 1

August Weismann’s theory of nuclear determination

Answer 1

Aka germ plasm theory

Embryos as mosaics
Nuclear determinants (not known at this time) responsible for different cell types
Gwen cells considered special case as five rose to all cell types
Eg. Muscle/blood/neuronal cells from different nuclear determinants

Question 2

Wilhelm Roux’s experiment

Answer 2

Stuck a hot needle in one cell of a fertilised frog egg at the two cell stage

Only half of the blastula and half of the neurala formed normally

Support for Weismann’s theory

Question 3

Fate maps

Answer 3

Dye can be injected into cells to allow them to be tracked and their fate to be observed

Don’t inform us about the states of cell determination

Allow description of anatomical and behavioural changes