BIOS E-1a Lecture 16 120511 annotated

BIOS E-1a Lecture 16 120511 annotated - Lecture 16: Human...

Info iconThis preview shows pages 1–17. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 16: Human Genetics Reading: Chapter 14 1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Development • Refers to a series of changes in the state of the cell, tissue, organ, or organism • Underlying process that gives rise to the structure and function of living organisms • Developmental genetics aimed at understanding how gene expression controls this process
Background image of page 2
General themes • Sperm and egg unite to produce a zygote • The zygote, a diploid cell, divides and develops into the embryo • Cells divide and begin to arrange themselves • Each cell becomes determined (destined to become a particular cell type) • Commitment to become a particular type of cell occurs long before a cell actually differentiates 3
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 • Genome is a set of genes that constitute the program of development • Unicellular organisms: controls structure and function of the single cell • Multicellular: controls cellular features and the arrangement of cells
Background image of page 4
5 Model organisms • Fruit fly Drosophila melanogaster – Advanced techniques for generating and analyzing mutants – Large enough for easy study but small enough to determine where genes are expressed • Nematode worm Caenorhabditis elegans – Simplicity: only about a thousand somatic cells – Pattern of cell division and fate of each cell known
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
6 • House mouse Mus musculus •Z e b r a f i s h Brachydanio rerio • Thale cress Arabidopsis thaliana – Wild mustard family – Short generation time, small genome
Background image of page 6
7 Pattern formation • Coordination of events leading to the formation of a body with a particular morphology • Formation of an adult body –An ima ls • Dorsoventral, anteroposterior, and left-right • May also be segmented – Plants • Root-shoot axis in a radial pattern
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
8 Body plan axes
Background image of page 8
9 Positional information • Each cell in the body must become the appropriate cell type based on its relative position • At appropriate times during development, each cell receives positional information that tells it where to go and what to become • Cell may respond by – Cell division, cell migration, cell differentiation, or cell death (apoptosis)
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
10 (a) Cell division (b) Cell migration (c) Cell differentiation (d) Cell death (apoptosis) Undifferentiated cell Nerve cell Cellular responses to positional information
Background image of page 10
Spemann graft: an embryonic organizer can produce instructive cues 11
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
12 Processes promoting limb formation
Background image of page 12
13 • 2 main mechanisms used to communicate positional information – Morphogens – Cell adhesion
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
14 Morphogens • Give positional information and promote cellular changes • Act in a concentration dependent manner with a critical threshold concentration • Distributed asymmetrically – In the oocyte or egg precursor – In the embryo by secretion and transport • Induction: cells govern fate of neighboring cells
Background image of page 14
Oocyte Gene product at anterior end (a) Asymmetric distribution of morphogens in the oocyte Cells secreting a morphogen Diffusion of morphogen to neighboring cells of an embryo (b) Induction: Asymmetric synthesis and extracellular distribution of a morphogen 15 Morphogen signaling
Background image of page 15

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The “French flag” analogy for morphogen gradients 16
Background image of page 16
Image of page 17
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/09/2012 for the course BIOLOGY 102 taught by Professor Anderson during the Spring '11 term at Harvard.

Page1 / 68

BIOS E-1a Lecture 16 120511 annotated - Lecture 16: Human...

This preview shows document pages 1 - 17. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online