genetics Flashcards
learning objectives
What is behavioural genetics
how genes and the environment interact to influence behaviour, traits and brain functions
What is epigenetics
the study of changes in gene expression and how the environment affects it
What is behavioural genomics
how DNA and specific genes are related to behaviour
Describe the nature vs. nurture debate and explain why it is difficult to study
“What causes our behaviour?”
Nature- genetics
Nurture- our environment and interactions with others
difficult to study because we don’t know how they influence each other
Describe the procedure for adoption and twin studies
identical twins: one sperm and egg cell divide into 2 zygotes with identical chromosomes
vs
fraternal twins: 2 eggs and two sperm that result in 2 zygotes with different chromosomes
Discuss why twin studies are done and what we can learn from them
compare the similarity between identical (monozygotic) twins and fraternal (dizygotic) twins
What if identical twins are more similar than fraternal twins
Discuss the influence of heredity on genotype
50% genetic material from each parent
50% probability shared genes between siblings
Define phenotype and genotype
genotype: genetics
phenotype: expression
define dominant
if you have one copy of this version you will have this trait
define recessive
you need both copies of this version to have the trait
Define epigenetics
changed to the expression of genes but not the underlying genes themselves
example: identical twins who look more different as they age
describe DNA methylation in epigenetics
changes that generally reduce the expression of a gene
descrive histone modification in epigenetics
changes that can either increase or decrease expression of a gene
Describe the role of childhood experiences, childhood nutrition in affecting gene expression
bond with parents influences stress response which can influence memory/attention/emotion
nutrition: famine in pregnancy increases risk of insulin resistance in offspring in adulthood
Define heritability
how much of the variation in a particular trait is attributable to variation in genetics
Describe the heritability coefficient
1.0= all of the variability
0.0= none of the variability
discuss differences in heritability of different traits
height is the highest (0.80) and school achievement (0.40) is the lowest for estimates
Define reaction range and describe how it affects phenotype
expressed characteristics of an organism depend both on genetic characteristics and the environment
Define familial environmental and unique environmental factors and give examples
familial environment: same parents, same house etc
unique environment: friends, hobbies, sports etc
Describe natural selection
ancestral populations characterized by phenotypic variation, heredity and differential fitness evolved adaptations that were crucial to individual reproduction and/or survival
Distinguish between selection for survival and selection for reproductive ability
selection for survival: traits raise survival success
selection for reproduction: traits lower survival rare but increase reproductive (bright colours on birds)
Describe sexual selection theory, including intra sexual competition and intersexual selection
some traits lower survival success, but increase reproductive success
what is intrasexual competition
competitions between members of the same sex for the ability to mate
it reduces survival success, but traits of winner are passed down
what is intersexual selection
choice of mate is influenced by various characteristics, which are then more likely to be passed down
