Molecular Biology C SSheng Zhao ( 赵晟 ), Biochemistry and Molecular Department of Medical school in Southeast University CCouse QQ Club: ( 分子生物学 C ) WWeb: E or QQQ /MSN/Skype/gChat: MMobile: or Conception, theory, research, and application ——Logic and LIY (Learn It Yourself)

Section 1 : “Lie still ！ ” vs. “ Ideal is far, while the love is waiting within a foot of~” ——Two different Chinese translations from ordinary younker ( 普通青年 ~) and literary youth （文艺青年 ~ ） for a sex behavior: Lordosis (The neural circuits behind behavior) Section 2 : How to prove your happiness? ——Happiness and sadness discovered by behavior (From psychological quiz to neural mechanisms) Case 5 : Choose natural controls ——The paired opposite behavior phenotype in clinic disease (Disease models with paired control) Chapter 5: Behavior + Science = Arts (Behavior tools for mechanism research)

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Twin studies reveal the absolute and relative importance of environmental and genetic influences on individuals in a sample.

Hippocrates attributed similar diseases in twins to shared material circumstances.

Edward Thorndike  use of twins to study the role of genes and environment on human development and behavior  unaware of the difference between identical and DZ twins

Hermann Werner Siemens( , German geneticist ) He was the first to not only use twins in a study (to determine the role of genes over environment in skin moles), but to distinguish identical from fraternal twins, and use the correct 100%/50% genetic similarity inferences regarding these groups.

 Monozygotic Twins(MZ) share nearly 100% of their genes  Dizygotic Twins(DZ) share only about 50% of their genes

classic twin study  genetic effects (heritability);  shared environment - events that happen to both twins, affecting them in the same way;  unshared, or unique, environment - events that occur to one twin but not another, or events that affect each twin in a different way.

classic twin study ACE model ： A (additive genetics) C (common environment) E (unique environment) r mz = A + C r dz = ½A + C A = 2 (r mz – r dz ) E = 1 – r mz C = r mz – A

Modern modeling Beginning in the 1970s, research transitioned to modeling genetic, environmental effects using maximum likeihood methods (Martin & Eaves, 1977). standardized A = A/(A+C+E)

Modern modeling Multi group and multi-variate modeling This is invaluable in answering questions about the genetic relationship between apparently different variables MZ discordant designs As MZ twins share both their genes and their family-level environmental factors, any differences between MZ twins reflect E （ epidemiologial tests ） Sex differences Genetic factors may differ between the sexes, both in gene expression and in the range of gene × environment interactions A standard analytic workflow would involve testing for sex-limitation by fitting models to five groups, identical male, identical female, fraternal male, fraternal female, and fraternal opposite sex.

Criticisms of statistical methods heritability estimates used for most twin studies rest on restrictive assumptions which are usually not tested, and if they are, can often found to be violated by the data. Twins as representative members of the population Twins are not a random sample of the population, and they differ in their developmental environment. In this sense they are not representative

刘军 Genetic and Environmental Effects on Same-sex Sexual Behavior: A Population Study of Twins in Sweden Niklas Langstrom ； Arch Sex Behav (2010) 39:75–80

7,231 men 10,676 women 11,229 men 14,096 women 21,481 men 21,607women Method

Two variables any lifetime same-sex partner total number of lifetime same-sex partners

R ESULTS Fewer men than women reported any lifetime same-sex sexual partner. v2(1) =32.11, p<.001 men407/ % women835/ % The average number of same-sex sexual partners was in men and 3.53 in women. Wilcoxon rank sum test = 8.75,p<.001 men12.86 women3.53

A weak negative correlation between any lifetime same-sex partner and age in women, rho =.05,p<.001, But not in men, rho =.01, p <.24

Heritabilit y(%) Unique Environme ntal(%) Shared Environme ntal(%) MenAny lifetime same-sex partner Total number of same-sex partners WomenAny lifetime same-sex partner Total number of same-sex partners

CONCLUSION In conclusion, although confidence intervals were wide, we believe this study provides the most unbiased estimates presented so far of genetic and non-genetic contributions to same-sex sexual behavior. The results should inform further research on this complex trait.

133817— 凌志新 Genetic and environmental influences on sodium intake determined by using half-day urine samples: the Healthy Twin Study. Am J Clin Nutr Dec;98(6): doi: /ajcn Epub 2013 Oct 2.

BACKGROUND Salt is essential in our diet, but excess intake is a well-established risk factor for hypertension. The presence and importance of genetic contributions to salt intake, however, are not well understood. So what’s main factor to salt overtaken? Gene or environment? OBJECTIVE: The aim of this study was to examine whether a genetic predisposition and an environmental influence exist for sodium intake and salt habit.

results half-day urine samples 1204 individuals Method

Collecting data heritability (h2) genetic factor intraclass correlations--- environmental factor

R ESULTS The average sodium intake was ± mmol/d. Men had a higher absolute sodium intake (242.6 ± mmol/d) average208.4 ± mmol/d men242.6 ± mmol/d Na-D did not differ by sex men242.6 ± mmol/d （ sodium ） 2180±180 calorie women174.1±97.8mmol/d （ sodium ） 1850±50 calorie

Moderate genetic influences existed (h2 = ) for sodium intake and Na-D (sodium density per calorie). We also found that sharing current residence rather than being a family member explained 22% of the variance in Na-D. CONCLUSION: Our findings suggest that both genetic predisposition and shared environment contribute to sodium intakes and salt habits alike. The results should inform further research on this complex trait.

姓 名 刘艾佳 Genetic and environmental influences on restrained eating behavior LOGO 学 号

Conclusions The reserchers found compelling evidence for a genetic contribution to restrained eating. A EC A: additive genetic factors C: common environmental factors E: unique environmental factors

personality factors body weight body composition additional metabolic factors inherited pathways Genetic contributions to restrained eating

Nevertheless, these data strongly suggest that additive genetics underlies the behavior pattern,implying the possibility of a direct effect from multiple genes inherited together. SEX Genetic contributions AGE × ×

Limitations of this study could have been subject to response bias limitations cannot verify the underlying assumptions used conventional epidemiologic methods had a relatively small number of DZ pairs used self-reported measures of weight and height cannot necessarily be generalized to other racial groups

Advantages of this study represents the largest twin study demonstrated the relationship interpreted the findings substantiates the inherited nature advantages

Further studies Interventions to reduce the risk of disordered eating could be targeted to the appropriate risk groups. Further studies specific genes gene-environment interactions inherited factors clarify the genetic, physiological, cognitive, and environmental factors