Mechanisms of Development Flashcards
1
Q
similarities across species
A
- vertebrate species begin with similar structure but become less alike each other as they develop
- similar genes and mechanisms have been found to control similar developmental processes in different animals
2
Q
genetic similarity
A
- similarity in dramatically different animals
- 20,000 genes in humans and nematodes
- 14,000 in fruit fly
- ~40% of human genes are present in flies and worms
- ~92% of human genes present in mice
- of 4,000 genes studied, less than 10 are in one species and not the other
- both mouse and humans have 3.1 million bp and similar number of genes
3
Q
mechanisms that drive developmetn
A
- genes and environment
- cell proliferation, specialization, interaction, and movement
- carried out by cell-cell communication
4
Q
homologous genes
A
- function interchangeable during development of different species
- gene similar in structure and evolutionary origin (and likely function)
- drosophila gene in mouse embryo has same effect as original gene
5
Q
model organisms
A
-due to similar mechanisms of development and homologous genes, researchers can use model organisms to study embryology under the premise that genes and mechanisms that control a specific aspect of development in one species are likely to play a similar role in that process in other species
6
Q
how do genes drive development?
A
- before genome sequencing, there were 2 hypothesis
1. difference in cell type comes from different sets of genes in different cells, and some cells lose genome
2. genes in all the cells are the same, they are just expressed differently- turns out to be the right one
7
Q
genome equivalence
A
- all cells contain the same set of genes
- different cells express different sets of genes
8
Q
somatic nuclear transfer
A
- aka cloning
- provides evidence that all cells contain the same genes
- cuz they can take somatic cell and put it in an egg and make it grow
- electrical pulses activated development
- nuclei of vertebrate adult somatic cells contain all of the genes necessary to generate and adult organism- no genes necessary for development have been lost
9
Q
differential gene expression
A
- only a small percentage of the genome is expressed in a cell type
- regulatory regions and proteins
- controls fundamental cellular processes-proliferation, movement, specialization, interaction
10
Q
gene expression regulation
A
- differential gene transcription
- selective nuclear RNA processing
- selective mRNA translation
- differential protein modification
- RNA in situ hybridization is a technique used to detect mRNA expression in cells/tissues
11
Q
induction
A
- one group of cells changes the behavior of an adjacent set of cells
- can be short range or long range
- need inducer, responder, and the responder cells have to be competent- have ability to receive signal
12
Q
ectodermal competence and the ability to respond to optic vesicle inducer
A
- normal induction of lens by optic vesicle
- optic vesicle can’t induce ectoderm that isn’t competent/ in the wrong place
- if there is no optic vesicle, no induction
- tissue other than optic vesicle doesn’t induce ectoderm
13
Q
competence
A
- actively acquired
- pax6 makes ectoderm competent to respond to inductive signals from optic vesicle
- one copy leads to aniridia
- no pax 6 means no eye
14
Q
signal transduction
A
- juxtacrine-contact between cells
- paracrine- diffusion of inducers
15
Q
paracrine factors
A
- proteins that are secreted into extracellular space and deliver signals to neighboring cells
- all morphogens are paracrine signals but not all paracrine signals are morphogens
