Developmental Patterning in Eukaryotes

What does developmental biology integrate

Genetics, biochemistry, cell biology, and evolution

What is the first stage of development in multicellular organisms

a single fertilized egg (zygote) divides to form an embryo

Name five common principles of developmental processes

cell division, cell signaling, differential gene expression, cell movement/expansion, programmed cell death

What leads to different cell types in multicellular organisms

a program of differential gene expression

What is cell differentiation

the process by which cells become specialized in structure and function

What is the role of programmed cell death (apoptosis) in development

shapes tissues and organs (removing webbing between toes

Are differentiated cells genetically equivalent

Yes, they contain the same genes but express different ones

What experiment demonstrated genetic equivalence

Cloning of Dolly the sheep

What is pattern formation

the spatial organization of tissues and organs

What provides cells with positional information

molecular cues that tells cells their location relative to body axes

What organism helped identify developmental control genes

Drosophila melanogaster (fruit fly)

Who won the 1995 Nobel Prize for discovering developmental genes in Drosophila

Christiane Nusslein-Volhard, Eric Wieschaus, and Edward B. Lewis

What are maternal effect genes

Genes from the mother that establish body axes in the embryo

What does the bicoid gene control

the formation of anterior structures in Drosophila

What are Hox genes

master control genes that regulate body patterning

What is homeosis

transformation of one organ into another due to Hox gene mutations

How are Hox genes evolutionarily conserved

they exist in clusters across many animal species and determine similar body structures

What happens when developmental processes are disrupted

the embryo may die, or the organism may develop novel traits

How do snakes lack forelimbs

due to continuous expression of Hoxc6 and Hoxc8

What caused hindlimb loss in snakes and whales

the loss of the sonic hedgehog signaling molecule