Genes Flashcards
phenotype
observable characteristics
- behaviour + products of behaviour
- dev process
- morphology
genotype
complete set of genetic material
allele
variant of given gene
mendelian inheritance
- unitary (white or blue)
- one dominant other recessive
- random segregation
- unlinked genes (independent assortment)
independent assortment in modern terms
unlinked genes
molecular gene
sequence of nucleotides in DNA that get transcribed to produce functional RNA
chromosome
long DNA sequence w packaging proteins
packaging protein in eukaryots
histone
non-mendelian inheritance
- incomplete dominance
- codominance
- polygenic inheritance
incomplete dominance
phenotype of heterozygous different from phenotype of homozygous
codominance
both alleles for gene expressed
- cows with brown and white spots
multiple alleles
genes exist in several diff forms
- A, B, O blood types
lethal alleles
cause organism death
- growth + dev genes
- can be dominant or recessive
pleiotropy
one gene influences 2+ phenotypes
antagonistic pleiotropy
gene beneficial + harmful
- beneficial early in life bc natural selection
polygenic
2 + genes for 1 phenotype
- bell curve
multifactorial inheritance
polygenic + environmental factors
quantitative inheritance
expression of trait depends on many genes
epistasis
interactions with other genes (non-allelic modifier genes)
- effect masked by different genes
- eg baldness masks bonde + red hair
polygenic inheritance model problems
- independent inheritance of genes
- no epistasis
- all genes hold equal sway over expression
threshold trait
inherited quantitatively but expression qualitatively
- schizophrenia traits only act up after threshold
gene penetrance
likelihood of gene expression
gene expressivity
variability of phenotype when allele is penetrant
factors in penetrance + expressivity
1 genetic background (epistasis)
2 temperature
3 food
4. sex limited
5. sex influenced
sex limited genes
present in both sexes but turned off in one sex
sex influenced genes
same gene differential expression in diff sexes
sex linked traits
gene is on a sex chromosome
- x dominant
- x recessive
- y linked
sex linked traits diseases X chromosome
- haemophilia
- fragile x syndrome
- colour blindness
partially imprint
alleles from both parents expressed rather than complete expression (+ suppression) of one gene
genomic imprinting
gene expression depends on if you’ve inherited it from mother or father
sexual antagonism
two sexes have conflicting fitness strategies with sex
heritable variations of genes
- recombination (crossing over)
- mutation
epigenetics examples
- environment
- food
- exercise
epigenetics
heritable phenotype changes without changing DNA sequence
PKU
mutation, causess low levels of phenalynyl hydroxylase
treatment: diet, low levels of phenylaline
sex chromosome abnormalities
- XXY (Kleinfelter) - small testicles
- XYY (Jacob’s) - taller, aggressive
- XO (Turner) - normal IQ but bad spatial so problems with maths
- XXX - learning disabilities + taller
autosomal chromosom abnormalities
- trisomy 21
- Angelmann (small head + severe learning disabilities)
- Prader-Wili Syndrome - from father, obesity + diabetes
Androgen Insensitivity Syndrome
- XY but phenotype female
- sex dev bc androgen receptor dysfunction
- small testes
- infertility
CAH hormone
- more male-type behaviour
- stronger amygdala activation to faces w negative emotions
- hippocampus less activated for face recognition
PCOS hormone
higher androgen level, causes homosexuality
AIS hormone
- brain feminization
- testosterone to estradiol
Autism increases with hormone
fetal T
heritability
estimation of phenotypic variability
genotype environment correlations
- passive gene influences (parents genes + environment they create)
- evocative gene influence
- active gene influence
active gene influence explained
kids pick out environments that suit their genetic predispositions
trad methods of behavioral genetics
- twins
- adoption
- family
big 5 factors with personality
- extraversion
- openness
- neuroticism
- agreeableness
- conscientiousness
Vasorepression receptor gene long
- what kind of person are they
altruistic