• Read Chapters 10 & 11 (10thedition; Ch 2 & 3 for 9thedition)• Stopwatches are ready for this week’s Discussion Section• Have at least 1 idea to discuss for Independent Research Projects• How to Study for ExamAnnouncements1Sample Exam Question1.(15 pts) The figure below depicts the average honeybee life cycle. Describe the proximate mechanisms that allow the shift from the first four stages of in-hive duties (nursing-type duties) to outside hive duties (foraging) (3pts). Explain how researchers disentangled age effects from the action of a single gene in this transition (5pts); describe the environmental regulation of this gene’s expression (3pts); and explain at an ultimate level why this gene may be environmentally-regulated, as opposed to environmentally-independent (as in another insect species) (4pts).2Questions• Are behaviors a product of Nature (innate/fixed) or Nurture (environment)?• How can single genes influence complex behaviors?• Why might some behaviors be regulated by environment for some species & regulated by genotype in another?• What are the mechanisms that regulate behavioral plasticity?• What are the molecular mechanisms by which the environment might alter behavioral phenoytpes?3Questions• How can behavioral plasticity be regulated?– Maternal Care– Reproductive Strategies– Anti-predatory Responses4The nonapeptide lectureDonaldson & Young 20085prairie volemontane voleWhat do we know about the proximate mechanisms of male monogamy in voles?Ventral Pallidum has higher V1a Receptor expression in Monogamous volesAVP produces different socialResponses betw.The 2 speciesVa1 Receptor Genes differ in upstream microsatellite length…possibly producing expression diff?6Looking across the Genus?• Fink et al 2006• Built a phylogeny of the avpR1 short tandem repeats (STR) in the regulatory region• No relationship between monogamy and STRs across voles(figure from Phelps et al. 2010, based on Fink et al 2006)prairiemeadowmontane7But what about the other mammals?• Schematic of the STRs in the 5’ region of various mammals (Fink et al 2006)ChimpanzeesHumans & Bonobos8Genetic Mechanisms of Pair Bonding in Humans:• Examined Human variation in the AVP receptor promotor region and its association with pair-bonding behavior• Genotyped males in a Swedish Twin Study (522 same sex twin pairs)• All subjects filled out a questionaire evaluating– Pair Bonding Score– Threats to Marriage; & – Marital StatusWalum et al 20089Vasopressin & Pair Bonding in Humans: A modified candidate Gene Approach (Walum et al 2008)Found a significant association between the RS-3 repeat polymorphism and PBS scores for Men only. And……found that the association was related to a specificAllele (allele 334)….and that it was NEGATIVE10Vasopressin & Pair Bonding in Humans: (Walum et al 2008)11Vasopressin & Pair Bonding in Humans: (Walum et al 2008)12Vasopressin & Pair Bonding in Humans: (Walum et al 2008)13• Which study (Voles or Humans) provides more evidence for a role in repeat elements/microsatellites in regulating monogamous behavior AND why?• What are some of the problems with the Human study?• Imagine you were an alien biologist studying monogamy on earth. You’ve seen the data for the prairie and montane vole research, and now you’d like to determine if similar mechanisms are at play in regulating human monogamous behavior. What experiments & predictions would you make? 14Questions• Are behaviors a product of Nature (innate/fixed) or Nurture (environment)?• How can single genes influence complex behaviors?• Why might some behaviors be regulated by environment for some species & regulated by genotype in another?• What are the mechanisms that regulate behavioral plasticity?• What are the molecular mechanisms by which the environment might alter behavioral phenoytpes?15-------------------------• Nature • NurtureThe Nature vs Nurture ContinuumGenes are inherited & also responsive to the EnvironmentEpigenetic Effects of Maternal Care16Maternal Behavior• Behaviors:– Licking and grooming (LG)– Arched-Back Nursing (ABN)– Latency to mother new pups• Good moms: high LG ABN• Poor moms: low LG ABN• Daughters of Good Moms-> HIGH LG ABN• Daughters of Poor Moms-> Low LG ABN• Genetic?– Variation in Oxytocin Receptors??17Is Maternal Behavior Heritable?•Michael Meaney & Colleagues tested this with a Cross-Fostering experiment•4 groups of Good Moms (high LG-ABN)•4 groups of Poor Moms (low LG-ABN)•3 controls + 1 Cross-Fostered Treatment per group•Controls = (i) Left alone with Mom;(ii) Removed & Returned to Mom(iii) Reared with Different Mom of Same LG-ABN Francis et al. 199918G G G GP P P PFOSTER MOMGOODPOORBIOLOGICAL MOMFemale Offspring Maternal PerformanceControl Pups?Treatment Pups?Francis et al. 1999Controls: 1. Left alone with Mom; 2. Removed & Returned;3. Reared w/ Diff Mom of Same LG-ABN19G G G GP P P PFOSTER MOMGOODPOORBIOLOGICAL MOMFemale Offspring Maternal PerformanceControl Pups:Francis et al. 1999Controls: 1. Left alone with Mom; 2. Removed & Returned;3. Reared w/ Diff Mom of Same LG-ABN20G G G GP P P PFOSTER MOMGOODPOORBIOLOGICAL MOMFemale Offspring Maternal PerformanceGenes x Environment?This is Environment!!Control Pups:Treatment Pups?Francis et al. 1999Controls: 1. Left alone with Mom; 2. Removed & Returned;3. Reared w/ Diff Mom of Same LG-ABN21Cross-Fostered Environment Determined the type of Maternal Behavior & Fear ResponseFemale Offspring Exploration BehaviorG G G GP P P PFOSTER MOM22What Selection Pressures Drive Parental Care?• Parental Investment=• “Any investment by the parent in an individual offspring that increases the offspring’s chance of surviving (and hence RS) at the cost of the parent’s ability to invest in other offspring”• Invest Now or Later?Trivers 197223What Selection Pressures Drive Parental Care?• What neural responses may mediate the “now or later” parental investment response?• If Current vs Future reproductive success is determined by current condition, then….• Is the Stress Response linked to parental care?24Variation in Maternal Careis it Genetic or Environmental? & what’s stress got to do with it?• High Quality Moms (lots of licking and grooming) produce high quality moms-to-be• Low Quality Moms (little licking and grooming) produce low quality moms-to-be• Cross-Fostering Experiment• ‘Genotype’