Midterm 1 for the final

Question 1

What is a cell fate determinant

Answer 1

Any molecule which can be unequally segregated between cell and leads to the specification of one daughter cell

Question 1

Give an example of a cell fate determinant

Answer 1

Pie-1 in the P1 cell

Question 2

What is a maternal effect gene

Answer 2

Maternal effect gene is a gene found in the oocyte that gives rise to proteins or MRNA present in the oocyte before and/or after fertilization but before zygotic genes are transcribed

Question 3

Give an example of a maternal effect gene

Answer 3

An example of a maternal effect gene would be biccoid which organizes the A-P axis through interactions with caudal and HB

Question 4

Discuss the differences in drosophilla HOX vs Vertebrate HOX gene

Answer 4

1)Vertebrates have more HOX genes and more HOX gene clusters
2)Flies pretty much express one hox gene per segment
3)Hox gene overlapping is common in vertebrates

Question 5

Describe 2 different ways to set up the A-P axis in an embryo

Answer 5

1)Asymmetrical division like in C.elegans the AB cell is the anterior and the P1 cell ends up as the posterior
2)Bicoid localizes in the anterior and nanos in the posterior. Nanos prevents translation of HB and Bicoid prevents translation of Caudaul. Biccoid acts as a transcription factor to activate anterior genes and as translational repressor to suppress posterior genes. Caudal acts as a transcription factor to
activate posterior genes and Nanos as translational
repressor to suppress anterior genes