The document discusses how genes determine the physical traits of organisms and behavior. It explains that genes are made up of four chemical bases that bond together to form DNA and RNA. Gene expression involves transcribing genes into RNA and translating RNA into proteins. Identical twin studies show that both genetic and environmental factors influence human behavior and psychology. Research on animal models and genetic mutations provide evidence that specific genes contribute to behaviors like circadian rhythms, feeding, and locomotion.

1. Genes and Behavior Kandel Chapter 3

3. Hydrogen bonds between C and G, and between T and A determine the stability of the “double elix” forming DNA and other similar nucleic acids

4. Human cromosomes

5. Crush course in gene expression: Gene expression = using genes for producing proteins There are only 4 nucleotide bases (T, C, A, G) and pairing is forced: (T-A and C-G) A gene is a sequence of bases encoding for a protein . Cromosomes (DNA, in the nucleus) are series of genes linked together (exons, ~5% of the total length) , with long non-coding regions inpterposed in between (introns, ~95% of the total length )

12. Identical Twin Studies - Raised Apart - Raised Together

13. Psychological features dependent on genetic or on environmental factors in three different studies

14. Knock-in or knock-out transgenic animals are valid tools for neuroscience research

16. In Drosophila two genes linked to circadian oscillations have been thoroughly studied: PER(iod) and TIM(less) genes They act in tandem as inhibitors of transcription. One of them is light-sensitive: light impairs its function and the complex stops working as transcription inhibitor

20. In mice a circadian rhythm gene has been identified: CLOCK Yellow indicates light. The black dots represent motor activity (mice are nocturnal animals) Circadian rythms are compromised in the -/- homozygotic animal

22. Huntington disease: As in many other genetic diseases, the mistaken repeat of a triplet (CAG) produces an anomalous protein, of yet unknown function, that is associated with HD symptoms. The longer the repeat, the younger the age of onset of the disease.