L3 Flashcards
DNA
2 strands of a sequence of 4 chemical bases (adenine, thymine, cytosine, guanine) arranged in complementary pairs
Heredity
the transmission of genetic information across generations and how it translates to differences in physical characteristics and behavior
Heritability
an estimate of the variability in the expression of a trait in a population that is attributable to genetic differences among those individuals
closer to 1 = genes account for variability
Genes
sections of DNA that code for specific proteins
Regulatory DNA
- regulates genes (on/off switch throughout life that can be built-in or influenced by the environment)
- malfunction can lead to regulator-gene defects
Chromosomes
23 pairs (22 pairs of autosomes and a pair of sex chromosomes) which contain our DNA
3 genetic processes that contribute to diversity
random assortment, crossing over, mutation
Random assortment
one of each of the 23 pairs of chromosomes randomly goes to a new egg or sperm during meiosis, resulting in new combinations of chromosomes in offspring
Crossing over
two members of a pair of chromosomes can swap sections of DNA during meiosis prior to random assortment
Main difference between random assortment and crossing over
- diversity at the level of whole chromosomes
- diversity within chromosomes
Mutations
random changes in genes within DNA
Alleles
different variants of the same gene that we inherit from each of our parents (one on each chromosome)
e.g. eye color and blood type
Autosomal dominant vs autosomal recessive
- only one allele is needed to express the trait in the phenotype
- both parents must pass the recessive allele for the child to express the trait
Codominant alleles vs incomplete dominance alleles
- both are expressed (e.g. AB blood type)
- blend of alleles (e.g. curly hair from a combination of straight and wavy)
Genotype vs phenotype
- unique genetic makeup of an individual (e.g. alleles)
- the way your genotype is expressed as influenced by the environment, or observable characteristics (e.g. height, IQ, personality)
Norm of reaction
all the phenotypes that could theoretically occur from a given genotype across all possible environments
Outcome of gene-environment correlations
kids become more like their genes due to their environments
Passive gene-environment correlations
child’s genotype is reinforced by the environment created by the parents who share the same genotype
Evocative gene-environment correlations
characteristics of the child elicit or evoke environments that support their genetic traits
Active gene-environment correlations
child seeks out environments or experiences that support their genetic traits
a process called “niche-picking”
Gene-environmental interactions
one’s genes make them particularly sensitive or susceptible to particular environments (e.g. PKU, MAOA)
MAOA
- X-linked gene known to inhibit brain chemicals associated with aggression
- high MAOA activity = less aggression
Methylation
epigenetic process wherein a methyl molecule binds to DNA and impacts (typically reduces) gene expression
