L6: Epigenetics & Brain Development Flashcards
What are the 2 types of migration?
1- Somal: An extension develops that leads to migration, cell body follows.
2- Gilal-Mediated: Cell moves along a radial glial network
How does axon migration work?
Axon tip becomes a growth cone and develops Filopodia. The filopodia feels for chemical signals in environment and guides axon.
What are the 3 stages for how a neural tube is formed in the embryo?
1) Folding around the neural plate produced the neural tube
2) Groove eventually closes up to create the neural tube
3) Central channel inside neural tube develops into cerebral ventricles and spinal canal
What are teratogens?
Environmental risk factors e.g. maternal infection/smoking/malnutrition
What are the 2 theories explaining why babies born in spring are more likely to develop schizophrenia?
1- Lack of sunlight can lead to Vitamin D deficiency
2- Mother catching infection in sensitive 2nd trimester; as babies born in spring coincide with autumn/winter flu
What are Permissive and Instructive experiences?
Permissive- a supporting environment that enables a behaviour to be expressed
Instructive- a signal from inducing cell is required for gene expression to occur
What happens if you deprive an animal of optical signals?
Synaptic connections between axons from the lateral geniculate and visual cortex becomes very impoverished.
What are the base-pairs for DNA?
Adenine - Thymine
Guanine - Cytosine
What are the 4 stages of gene expression?
1) Gene separates
2) Transcription
3) Translation
4) When ribosome reaches end of messenger RNA strand, a codon instructs it to release completed protein
Finish the sentence:
Gene-environment interactions can be…
passive, active and evocative
What are the 3 types of modifications?
1) Histone remodelling
2) DNA methylation
3) RNA methylation
What is Polygenicity and Plelotropy?
Polygenicity- When one characteristic is controlled by 2+ genes e.g. height, skin colour, eye colour, weight
Pleotropy- genetic effect of a signle gene on multiple phenotypic traits
What happened to the children who were malnourished in early vs late gestation during the Dutch Hunger Winter?
Early - born with normal weight, when grown up and had own children, they were born with increased birth weight
Late- children were born with decreased birth weight, but their children were born with normal birth weight
What have animal models taught us about genetics?
Mice who were shocked when it smelt cherry blossom, had offspring who became stressed when introduced to cherry blossom.
