Psych 350 1st Edition Lecture 8 Outline of Last Lecture I Identical twin study II variance III environmental affects IV behavior genetics study Outline of Current Lecture II Gene expression III Methylation IV Gestational Period Current Lecture environments cause differences in gene expression two identical mice mothers diet were different because of what their mother was eating caused changes on dna and chromosomes in this case thedna was methylated caused gene to b shut off yellow fur was not methylated gene was turned on and cause mouse to get yellow fur brown fur mothers diet was different and the gene was turned off environmental effect cause the change in gene expression in this cause it was mediated by methyl groups histone modification can be acelyated causes histones to open up and those genes will turned on and expressed video epigenetic of identical twins epigenome activates or stops genes from being expressed activate and silence different genes imprinted genes when epigenetic tags remain on genes twins share same environment so their epigenome is the same their genomes remain the same but the environment acts on their epigenome to activate and silence different genomes diet differences in physical activity exposure to toxins stress meythlation from two chromosomes These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute 3 years old take chromosome of one twin and put it on the other and where there is yellow it is overlapping 50 years old has little to no yellow Michael meanie uni of Montreal baby rats when they grew up some grew up and out in stressful situation would freak out others would be calm this depended on the birth of rats rats who mothers gave a lot of maternal care they were more tolerant to stress compared to rats who didn t get maternal care this occur because of an epigentic modification of a specific gene response of mammals to stress in humans cortisol go trough blood to various tissue and goes into brain and cause effects the females who freaked out in stress also turned out to be lousy mothers this change was due to methylation of a particular gene could this be happening in humans stress associated with depression and anxiety could this be mediated by epigenetic way PAPER involves same gene as in rats methylation of that gene in humans go to local state child services department that may have been mal treated and permission of parents examined record and found two group of kids 1 group documented evidence of mistreatment 2nd group no evidence of mistreatment they look at the gene when te kids were young kids they should see glucocodicode gene methylated if they have stress early in their life 13 sites promote regions saw how methylated 3 6 7 location there was a sign difference of methylation of dna early events kids are experience are causes changes in their dna that changes the genes that are expressed by the children during their lives environment having an impact on gene expression prenatal development of humans from conception to birth gestation 9 months long medical people divide it into trimesters 3 months long start of prego is not the time of conception scientists think two weeks alter from woman last menstrual period medical professionals first day of woman last menstrual cycle 2 weeks before conception biologist and embryologist look at events during prego start the time of fertilization last 38 weeks divide up prego into 3 1st two weeks germinal periods 2 10 embryonic 8 weeks 10 and above fetal 3o weeks medical pro first day of womans last menstrual 40 weeks describing length full term 39 40 weeks early term 37 38 pre term less than 37 late term 41 weeks 42or more 42 weeks growth of fetus chart is third term 3 5kgs 7 7 5 pounds most of growth in size occurs over the last weeks in prego beginning of 3rd the fetus weights about 1 pound desirable weight gains depends on weight before why gain so much weight for fetus placenta blood uterus breast other tissue fat stores fluid extracellular fluid fetal blood also more tissue development of fetus development of the follicle and oocyte during menstrual cycle one or two oova get big and forma follicle 1 cm and rupture and will be released into ovary early part release of egg into fallopian tube where it gets fertilized by sperm nuclear material of sperm penetrates into the cytoplasm of the egg and forma diploid fertilized egg