Chapter 20- Developmental patterning in eukaryotes

What does it mean that eukaryotic cells are genetically equivalent (except gametes)?

It refers to the fact that all mature plant and animal cells contain the same genes, and cell differences arise from differential gene expression.

What is cell differentiation?

The process by which cells become specialized in structure and function.

What primarily controls cell differentiation?

Gene expression, where not all genes in the genome are expressed in every cell.

What are transcription factors?

Proteins that bind to specific DNA sequences near genes to promote or inhibit transcription.

What are epigenetic modifications?

Chemical changes to DNA or histones that affect how tightly or loosely DNA is packed.

What are non-coding RNAs?

RNA molecules that do not encode proteins but play roles in regulating gene expression.

What is induction in developmental biology?

A process that influences the fate of another group of nearby cells through signaling mechanisms.

What does the term morphogenesis refer to?

The process by which cells, tissues, and organs develop their shape and structure during embryonic development.

Define maternal effect genes.

Genes from the mother that influence the development of the offspring, directing body structure through mRNA.

What happens if maternal effect genes are mutated?

This can lead to severe developmental defects in embryos, such as lack of body axis formation and severe patterning defects.

What is bicoid and its role?

A gene that affects the anterior (front) half of the body; it creates a morphogen gradient that determines head formation.

What are morphogens?

Signaling molecules that play a key role in the development of an organism, creating concentration gradients.

How did researchers confirm bicoid as a morphogen?

Through genetic experiments showing bicoid mutants lacked anterior structures and using in situ hybridization techniques.

What are homeotic genes?

Genes that determine organ formation and are essential for proper spatial organization within the embryonic development.

What is the significance of Hox genes?

conserved homeobox genes that dictate the body plan along the anterior-posterior axis and are crucial for proper development.

What can happen if Hox gene expression is altered?

It can lead to transformations in the identity of body parts, such as the emergence of legs in place of antennae.

What are developmental patterning genes?

Genes that guide the formation, identity, and positioning of various structures during embryonic development.

What is Sonic Hedgehog (Shh) and its significance?

A critical signaling molecule for limb development; loss or misregulation can lead to severe limb malformations.

How does gene expression control reveal evolutionary connectedness?

Many developmental processes and conserved genes are present across species, indicating shared evolutionary pathways.