Developmental Patterning in Eukaryotes

Developmental Biology

integrates genetics, biochemistry, cell biology, and evolution

Cell differentiation

is the process by which cells become specialized

in structure and function

Programmed Cell Death

is a highly regulated and essential part of

development

Apoptosis

is the most common type in

animals

• Cells that form webbing between

toes die

• About half of neurons die as nervous

system is wired

• Harmful immune cells are eliminated

Pattern Formation

is the development of a spatial organization of

tissues and organs

Positional Information

the molecular cues that control pattern

formation, tells a cell its location relative to the body axes and to

neighboring cells

Maternal effect genes

encode cytoplasmic determinants that initially

establish the axes of the body of Drosophila

Homeosis

is the transformation of one organ into another via mutation.

Homeosis is caused by

mutations in

Hox genes

Homebox (Hox) genes

guide pattern formation in

embryos - tell the cells

of the body how to

differentiate as the body grows

• occur in diverse

groups such as

• prokaryotes

• yeast

• plants

• animals

Egg-polarity genes

because they control the orientation of the egg and consequently the fly