behavioral genetics - chapter 4

proximate research

type of research that focuses on the immediate mechanistic causes of a biological phenomenon (like a behavior or a physiological process); it’s about “how” something happens

gene

specific segment of DNA that carries the instructions for building and regulating an organisms’s traits, including behavioral traits

allele

an alternate form of a gene

protein

biochemical compounds that have many functions; called the “building blocks” of life because they can be structural components of cells, tissues, and organs; function as enzymes by catalyzing chemical reactions, and they are an important component in cell signaling, functioning as neurotransmitters, hormones, or receptors; play a key role in initiating physiological changes in cells and organ systems that affect the brain and resulting behaviors

hormone

chemical messengers produced by endocrine glands that travel through the bloodstream to influence the nervous system and regulate various physiological processes and behaviors

sensory input

animals acquire this for both the abiotic and biotic aspects of the environment, including the presence of others, such as conspecifics or predators; detects signals from the outside environment and communicates it to the body via the nervous system

gene expression

the process in which gene products are produced; genes and their products are expressed at different times and in different environmental conditions, depending on sensory inputs

qualitative trait

traits that falls into a specific category + encoded by a small number of genes

discrete trait

traits controlled by a small number of genes, often only one; a characteristic that exhibits distinct, separate categories or phenotypes with no intermediate forms

single gene effect

a single gene influences many genes during development; the influence of a single gene on a specific behavioral trait or aspect of behavior

polygenic trait

a characteristic in animals that is influenced by more than one gene (ex: height, skin color); do not following the patterns of Mendelian inheritance; these traits result in continuous traits

quantitative (continuous) traits

this trait may theoretically assume any value between two limits

loci

location of a gene on a chromosome

instinct/innate behavior

behaviors performed the same way each time + are fully expressed the first time they are exhibited + and are present even in individuals raised in isolation; this behavior does not vary

major gene

individual genes that are responsible for the majority of phenotypic variation

minor gene

those that contribute to small amounts of variation + have less influence on behavior

phenotype

physical trait; consequence of genotype and environment

genotype

specific genetic makeup of an organism, particularly the alleles that influence its traits and characteristics, including behavior

additive effects

average effect of individual alleles on the phenotype

non-additive effects

genes the interact with each other

dominance effects

the interaction between alleles at one locus, in which one allele can mask the expression (phenotype) of the other

epistatic effects

the interaction between genes at different loci, such that one gene modifies the effect of another or acts with it to produce a new phenotype

allelic variation

the presence of different forms (alleles) of a gene at a specific loci on a chromosome, and how these variations can influence behavioral traits in animals

broad-sense heritability

proportion of phenotypic variance; includes all the genetic effects on the phenotype

narrow-sense heritability

the proportion of phenotypic variance is due solely to additive genetic values; can be determined by examining the similarity of behavior between parents and their offspring

parent-offspring regression

the mean trait values of parents are regressed against the mean trait values of their offspring

fixed action pattern

a behavior that displays almost no variation and, once started, is not stopped until completed

• ex: yawning

observational study

watching and recording the behavior of animals in their natural environment without manipulating any variables

knockout study

a procedure in which a single gene is rendered nonfunctional; used to understand how genetic variation is associated with behavioral variation → disable a gene and examine the effect on behavior

• disable gene and observe behavior

QTL mapping

statistical technique that combines genetic info with trait info to determine which regions of the genome contains genes that influence the trait

reflex

involuntary and often immediate behavioral responses to an external stimulus

microarray

an analysis that measures the amount of mRNA produced as an indicator of gene activation

• identify active genes and level of activity by measuring amount of mRNA produced for those genes

personalities

consistent differences in behavior over time or across different environmental contexts

behavioral flexibility

an animal’s ability to adapt its behavior in response to changing environmental conditions

gene-environment interactions

the complex interplay between genes and environmental factors that affect animal behavior and development

trait heritability

the degree to which genetic factors contribute to variation in a trait

mendelian inheritance

the pattern of traits being passed from parents to offspring where a single gene controls a specific characteristic

• ex: dominant and recessive alleles