H3 Genetics and evolutionary foundations of behavior Flashcards
Definition evolution
Long-term adaptive process, spanning generations that equips each species for life in its ever-changing natural habit.
Definition genes
Components of extremely long molecules of substance called DNA
What do they think is the function of DNA that does not code for proteins (junk DNA) at this point?
A.o. regulating activity of coding DNA
How are genes involved in long-term behavioral changes derived from experience?
Experiences activate genes, which produce proteins, which in turn alter the function of some of the neural circuits in the brain and thereby change the individual’s behavior.
Definition genotype
Set of genes that the individuals inherit
Definition phenotype
Observable properties of the body and behaviour
How can the same genotype produce various phenotypes?
By being exposed to different influences of the environment
What are chromosomes?
Structures in which the DNA exists in each cell
Definition mitosis
When a cell divides to produce new cells other than egg or sperm cells > exact copies of original cell.
Definition meiosis.
Meiosis results in egg and sperm cells that are genetically unique and contain only half the full number of chromosomes.
How does meiosis produce egg or sperm cells that are all genetically different from one another?
By crossover during meiosis
- Chromosomes replicate
- exchange genetic material through crossover (random assortment of paired genes)
- Divide
- Divide again
Definition zygote
When a sperm and an egg unite the result is a single new cell called zygote. Each zygote is unique.
What is the advantage of producing genetically diverse offspring?
Genetic diversity produced by sexual reproduction promotes survival of genes by reducing the chance that all offspring will die.
What is homozygote vs heterozygote?
Homozygote: two genes that occupy a locus on a pair of chromosomes is identical
Heterozygote: two genes that occupy a locus on a pair of chromosomes is not identical
Definition alleles.
Do all alleles manifest dominance or recessiveness?
Different genes that can occupy the same locus on a chromosome and thus can potentially pair with each other are called alleles.
No, some pairs blend their effects.
Why might a disease caused by 2 recessive genes persist in the gene pool?
Because having 1 recessive gene might serve a protective function, such as in sickle-cell anemia.
How do genes and the environment interact to affect individuals with phenylketonuria (PKU)?
Inability to process phenylalanine, which is in a lot of foods. Inability is caused by defective genes. But disease is only detrimental if individual etas foods with phenylalanine.
How do the characteristics that derive from variation at a single gene locus (single-gene trait) differ from those that derive from variation in multiple genes (polygenic trait)?
Polygenic: continuous phenotype with normal distribution
Single-gene: categorial phenotype
Definition selective breeding.
Mating of individuals that lie towards the same extreme on the measure in question.
Examples:
Tyron’s breeding of rats for maze ability and Russian program of breeding foxes for tameness.
Definition epigenetics.
What are twho mechanisms of epigenetic effects? When are genes turned on or off?
Changes in gene function that do not alter its underlying structure of DNA but result in genes being switched on or off in a reversible way.
Epigenetic effects can be transmitted to children and grandchildren without any changes in the genes themselves.
Methylation (turned off when highly methylated); histone modification (turned on when histone modified).