Week 6

Question 1

how does bicoid work?

Answer 1

bicoid regulates hunchback (hb) transcription in a dose response manner

• combinaatorial system regulates expression pattern of bcd-responsive genes
• gene regulatory (GRN) controlling gap gene expression

Question 2

generation of a repetative pattern from non-repeetitive signals

Answer 2

promotor fusions

• attachment of DNA fragments containing putative regulatory sequences to a reporter gene

Question 3

pair rule genes

Answer 3

even skipped (eve)

odd skipped (odd)

hairy (h)

runt (run)

fushu- tarazu (ftz)

Question 4

definition of parasegment

Answer 4

developmental units arranged along body of developing drophilia embryo, which give arise to segments in larva and adult

Question 5

homeotic mutations and discovery of Hox genes

Answer 5

based on his analysis of bithorax mutations Lewis proposed a model explaining function of Hox genes

Question 6

How is the expression and function of Hox genes controlled

Answer 6

transcriptional regulation by segmentation genes

• transcriptional activation from combination of segmentation gene products determine main areas of Hox gene expression during early development

chromatin based regulation

• later on what most segmentation gene products have decayed, Hox gene expression is maintained by epgenetic code (memory system)

rna based regulation

• recently RNA processing and microRNA regulation have been shown to be able to control Hox gene expression at different developmental stages

Question 7

homeobox

Answer 7

Homeobox, encoding homeodomain was first identified in homeotic selector genes of drosophila

Question 8

unexpected evolutionary conservation of Hox genes

Answer 8

hox genes display a similar genomic structure and expression patterns in most animal groups