Genes and Environment Flashcards
Pre-Darwin Observations
- fossil records showed that bones from older geological strata differ from recent strata
- structural similarities across diverse kinds of creatures body structure and embryological development
Charles Darwin Evolution
- there is genetic variation in species
- some genes aid in adaptation more than others
- these genes will be passed on to future generations (natural selection)
Genotype
the genetic makeup a person inherits
Phenotype
the actual characteristic or trait expressed
Darwin’s observations on H.M.S Beagle
- different beak shape and sizes on finches in the Galapagos Islands
- thought maybe living isolated on different islands had forced species to change and adapt to local conditions and that they share a common ancestor
Mutation
random genetic copying error (a few mutations will result in a reproductive benefit on an individual and these mutations will spread over time)
Adaptation
an evolved solution to a specific problem that leads to successful reproduction in some way
Fitness
how well-suited or matched an individual is to his/her environment
-reproductive success
Did humans evolve from living apes?
NO, humans and apes share a common ancestor that no longer exists
Evolutionary Psychology
an approach to the study of psychology that utilises modern evolutionary theory as a unifying frame
Zygote
union of sperm and ovum at conception
Where did humankind start?
Rift Valley in Africa
milk
most adults cannot digest the primary sugar in milk - lactase persistence found in northern europeans, nomads in africa and asia
Meiosis
- process producing sperm and ova
- start with diplod cells end with haploid gametes
Mitosis
cell division process creating new cells throughout life
Regulator genes
turn on or off specific genes
SRY gene
responsible for looking male or female
- used in the olympics as a gender verification
- athletes with SRY gene were not permitted to participate as females (until 2000)
males
females
xy
xx
3 major mechanisms by which genes are inherited
- single gene-pair
- sex-linked
- polygenic inheritance
(also mutation)
single gene-pair inheritance
-dominant genes: dominant trait
sex linked inheritance
-single gene located on sex chromosomes
-x linked
(hemophilia, colourblindness)
polygenic inheritance
- most nb human characteristics (height, weight, temperament, intelligence)
- multiple pairs of genes
chromosomal abnormalities: anatomical
- microcephaly
- hypopigmentation (fair eyes,skin hair)
chromosomal abnormalities: neurological
- seizures
- EEG abnoralities
chromosomal abnormalities: motoric
- hypertonicity (posturing)
- poor coordination
chromosomal abnormalities: behavioural
- hyperactivity
- attention problems
- lower IQ
Turner’s syndrome
- sex chromosome abnormality
- 1/3000 females have a single x chromosome
- short stature
- lack ovarian development
- webbed neck
- arms turn out at elbow
- low hairline in back of head
Klinefelter syndome
- sex chromosome abnomality
- 1/200 males
- XXY
- sterile, feminine traits
- underdeveloped testicles (hypogonadism)
- taller than average
- feminine body build
Phenylketonuria
- genetic inborn error of metabolism
- absence of enzyme that produces amino acid phenylalanine
- without treatment, develop mental retardation
- treatment: phe-restricted diet
- recessive trait
Sickle Cell Disease
- fatigue, breathlessness, arm and leg pains, foot swelling
- (anaemia)
- genotype: Ss
Huntington’s Disease
- hereditary, degenerative brain disorder
- no treatment or cure
- diminishes ability to walk, think, talk and reason
- single dominant gene
- symptoms at 30-45
- each child of a person with HD, has a 50% chance of inheriting it
- everyone who carries gene develops it
Behavioural Genetics
the extent to which genetic and environmental differences among people and animals are responsible for differences in their traits
Concordance rates
percent of pairs if one has the trait so does the other
Correlation coefficients
used to assess where traits vary together
Heritability estimate
a measure of the degree to which a variation in a particular trait among individuals in a given population is related to genetic differences among individuals.
H2 = 2(rm – rd)
3 factors of influences
- genes
- shared environment influences
- nonshared environmental influences
accounting for individual differences
-Correlations highest in identical twins —>
Genetic factors determine trait
-Correlations higher if twins reared together —->
Environmental factors
-Correlations are not perfect—->
Nonshared experiences
Identical twins more alike with age
Passive gene/environment correlations
parents create social home
Evocative gene/environment correlations
smiley baby gets more stimulation
Active gene/environment correlations
child seeks parties, friends, groups
Controversies Surrounding Genetic Research
- Identification of carriers of diseases and disorders
- Giving information which leads to abortion
- Experimenting with techniques for genetic alteration
- Better parenting if child’s genetic predispositions understood
Bioethics – sex selection
- in 1990s sex of embryos used for IVF via genetic diagnosis
- pro: harms no one, a private decision
- con: discriminatory effect on women
Gene slc24a5
responsible for skin colour variation
