PSY210H1 Lecture Notes - Lecture 3: Fetal Alcohol Spectrum Disorder, Retina, In Utero
Review: Hemophilia is hereditary. Down syndrome is not hereditary, it is a chromosome
abnormality, extra chromosomes.
Catherine has Hemophilia (XH XH ),
Behavioral Genetic: branch of genetic that deals with inheritance of behavioral and
psychological traits. Twin studies & adoption studies(compare children with the adopted
parents and biological parents).
Genotype: genes inherits from their parents.
Genotype intreat with environment to produce phenotype.
Range of creationL range of phenotypes that same genotype can produce in reaction to
the environment. In the extreme poor environment, they do poor. In the extreme rich
environment, they do extreme good.
Lecture 2: Prenatal Development continued…
Gene x Environment Pathways
•Behavioral Pathways
■People attract/select different experiences based on their genes.
■Niche-picking: people’s genes encourage them to seek out
experiences that are compatible with their inherited tendencies. If
the child inherit athlete gene, and the father is also an athlete, then
the father would choose some sports for you. Or the child will
choose the environment by themselves according to the genes that
parents pass to you.
•Genetic & Molecular Pathways
■Genes can determine how sensitive you are to the environment. Eg.
SSRI allele and life stress: short allele and long allele. Both in the
adverse environment, see the chance of development of depression.
If no instance of abuse, no depression will develop no matter short
allele and long allele. (ss, sl,ll), no maltreatment, no depression.
Probable maltreatment, people who have “ss” have higher chance
to develop depression. ll have less chance to develop depression. ss
do produce less protein. Same to the stressful life events, ss shows
higher chance to develop depression than ll, sl lays on the middle.
XH
XH
X
XHX
XHX
Y
XHY
XHY
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■Environment can influence genetic expression through epigenetic
markers.
Epigenetics: adjust the gene to the rapid change environment.
•The study of cellular and physiological trait variations that are not caused by
changes in the DNA sequence. Above the level of genetic.
•The study of external or environmental factors that turn genes on and off and
affect how cells read genes. add or remove the marker to effect the gene .
•2 Mechanisms: DNA Methylation: taking the methyl group to the DNA, down
regulate the particular gene, less likely to transcript into protein.
•& Histone Modification: coral protein around the gene. how easy to access that
gene. DNA wrap around histone.
•Epigenetic tags are a normal part of cell differentiation: each cell type in the body
is genetically identical but has different genes activated so they they can do
different functions (neurons, skin, etc)
•Epigenetic tags act like a cellular memory.
•As cells grow and divide, cellular machinery faithfully copies epigenetic takes
along with the DNA.
•In utero: Maternal stress, diet, etc… have can alter your epigenetic markers.
•Epigenetic markers can slo be added or removed in response to stress, maternal
behavior, diet, etc throughout the life span.
!
Dutch Hunger Winter: individuals live in Holland were starving in the winter. look the
baby in utero. In utero, there was famine, and early exposure and later exposure to famine
in the utero. Individuals who ere prenatally exposed to famine early in gestation had, 6
decades later, less DNA methylation of IGF2 gene compares with their unexposed, same-
sex siblings. Only early in gestation, won’t show at the last 3 months in gestation.
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•Only saw methylation differences in individuals that were exposed to famine early
in gestation
•As adults had higher rates of obesity than those born before and after the war and
higher rates than those exposed during mid- to late gestation
•Conclusion: early-life environmental conditions can cause epigenetic changes in
humans that persist throughout life
•Mismatch between early environment and later environment can be maladaptive
•epigenetic will set the gene according to the environment. What the mom eat
have to do with the weigh of the child after 16 years.
•Correlation study.
•Other example: rats. in utero during9/11? Mothering: licking & grooming—stress
response in rats.
Epigenetic inheritance:
• there is even some evidence that you can ass on your epigenetic markers to your
offspring.
• Parent’s experiences, in the form of epigenetic tags, can be passed down to future
generations.
Prenatal development
1) Zygote (first 2 weeks): conception to 2 weeks.
•Implantation into wall of uterus
2) Embryo (weeks 3-8)
•Develop amniotic sac
•Important physiological structures become differentiated
•Cells differentiate into 3 layers:
•Ectoderm: hair skin, nervous systems.
•Mesoderm: muscle, bone, circulatory system.
•Endoderm: lungs and digestive system.
•Develop amniotic sac: blood cell.
3) Fetus (weeks 9 - 38): majority of the pregnant
Ear and eye become structurally complete, rapid expansion of the cerebral
cortex & myelination of the spinal cord
22- 28 weeks = age of viability, if you give the birth at this period, it will
survive. the lung is not develop complete, need help the breath.
Prenatal development by trimester:
• First trimester (0-13 week): encompasses the zygotic, embryonic and beginning of feel
stage. Most body parts including the nervous systems and limbs are formed.
• Second Trimester (14-16 weeks): fetus is 12 to 15 inches long and mother can feel their
movement.
• Third Trimester (27-40 weeks): fetus reaches ages of viability. Ear and eye become
structurally complete, rapid expansion of the cerebral cortex & myelination of the
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Document Summary
Down syndrome is not hereditary, it is a chromosome abnormality, extra chromosomes. Behavioral genetic: branch of genetic that deals with inheritance of behavioral and psychological traits. Twin studies & adoption studies(compare children with the adopted parents and biological parents). Range of creationl range of phenotypes that same genotype can produce in reaction to the environment. In the extreme poor environment, they do poor. In the extreme rich environment, they do extreme good. People attract/select different experiences based on their genes. Niche-picking: people"s genes encourage them to seek out experiences that are compatible with their inherited tendencies. If the child inherit athlete gene, and the father is also an athlete, then the father would choose some sports for you. Or the child will choose the environment by themselves according to the genes that parents pass to you: genetic & molecular pathways. Genes can determine how sensitive you are to the environment. Ssri allele and life stress: short allele and long allele.
