Genetics and Evolution of Behavior

Question 1

Gregor Mendel

Answer 1

demonstrated that inheritance occurs through genes

Question 2

genes

Answer 2

units of heredity that maintain their structural identity from one generation to another

Question 3

chromosomes

Answer 3

strands of genes (arranged in pairs) that also come in pairs

Question 4

deoxyribonucleic acid (DNA)

Answer 4

a gene has been defined as part of a chromosome composed of the double-stranded molecule DNA

BUT, many genes do not have the discrete locations

sometimes several genes overlap on a stretch of chromosome. Sometimes a genetic outcome depends on parts of two or more chromosomes. In many cases, part of a chromosome alters the expression of another part without coding for any protein of its own.

Question 5

ribonucleic acid (RNA)

Answer 5

A strand of DNA serves as a template (model) for the syn- thesis of ribonucleic acid (RNA) molecules, a single-strand chemical

Question 6

messenger RNA

Answer 6

serves as a template for the synthesis of protein molecules.

Question 7

four “bases” of DNA

Answer 7

adenine, guanine, cytosine, and thymine

their order determines the order of the corresponding bases along an RNA molecule

Question 8

four “bases” of RNA

Answer 8

adenine, guanine, cytosine, and uracil.

he order of bases along an RNA mole- cule in turn determines the order of amino acids that compose a protein.

Question 9

role of proteins

Answer 9

Some proteins form part of the structure of the body.

Others serve as enzymes, biological catalysts that regulate chemical reactions in the body.

Not all RNA molecules code for proteins.

Many RNA molecules perform regulatory functions.

Question 10

homozygous

Answer 10

description for a particular gene for when you have the same genes on your two copies of some chromosome

Question 11

heterozygous

Answer 11

have an unmatched pair of genes

eg, might have a gene for blue eyes on one chromosome and a gene for brown eyes on the other

Question 12

dominant gene

Answer 12

shows a strong effect in either the homozy- gous or heterozygous condition

Question 13

recessive gene

Answer 13

shows its effects only in the homozygous condition

Question 14

Complications to Two Gene Determination

Answer 14

at least 10 genes that contribute to variations in eye color

At least 180 genes contribute to differences in people’s height

changes in the environment can increase or decrease the expression of a gene

Question 15

Sample of Regular Chromosome Differences

Answer 15

ADD IN PICS

Question 16

sex-linked genes

Answer 16

A gene on either the X or Y chromosome

genes on the sex chromosomes (designated X and Y in mammals)

usually mean X-linked genes

Y chromosome is small, with relatively few genes of its own, but it also has sites that influence the functioning of genes on other chromosomes

Question 17

autosomal genes

Answer 17

All other chromosomes are autosomal chromosomes, and their genes are known as autosomal genes, as opposed to sex-linked genes

Question 18

red-green color vision deficiency visual

Answer 18

ADD PHOTO!

Question 19

sex-limited genes

Answer 19

present in both sexes but active mainly in one sex

genes that control the amount of chest hair in men, breast size in women, amount of crowing in roosters, and rate of egg production in hens.

Both sexes have the genes, but sex hormones activate them in one sex and not the other, or one sex much more than the other. Many sex-limited genes show their effects at puberty.

Question 20

mutation

Answer 20

a heri- table change in a DNA molecule.

Changing just one base in DNA to any of the other three types means that the mutant gene will code for a protein with a different amino acid at one location in the molecule

Question 21

duplication or deletion

Answer 21

During the process of reproduction, part of a chromosome that ordinarily appears once might instead appear twice or not at all

Question 22

microduplication or microdeletion

Answer 22

when duplication or deletion happens to just a tiny portion of a chromosome

Microduplications and microdeletions of brain-relevant genes are responsible for several psychological or neurological disorders, probably including some cases of schizophrenia

Question 23

epigenetics

Answer 23

deals with changes in gene expression

all cells have the same DNA (except red blood cells which have no DAN)

but they get different genes turned on or off based on a number of factors

epigenetic changes can be inheritied for a limited amount of generations

Question 24

histones and process of epigenetic change

Answer 24

proteins that bind DNA into a shape that is more like string wound around a ball

histone molecules in the ball have loose ends to which certain chemical groups can attach

To activate a gene, the DNA must partially unwind from the histones

environmental factor changes the histone causing it to loosen or tighten grip on DNA facilitating change

methyl group turns genes off

acetylg roup loosens histone’s grip and increases gene activation

Question 25

heritability

Answer 25

if the variations in some characteristic depend largely on genetic differences, they are heritable

it is a range

Question 26

determining heritability

Answer 26

compare monozygotic and dizygotic twins

study adopted children

identify specific genes linked to some behavior

Question 27

candidate gene approach

Answer 27

researchers test a hypothesis, such as “a gene that increases the activity of the serotonin transporter may be linked to an increased risk of depression.”

has identified one gene with a significant influence on the risk of alcohol abuse, and a few other genes with moderate effects, but many studies have yielded small or uncertain effects

Question 28

genome wide association study

Answer 28

examines all the genes while comparing two groups, such as people with and without schizophrenia

Question 29

likely heritability from twin/adoption studies

Answer 29

loneliness, neuroticism, television watching, social attitudes, cognitive performance, educational attainment, speed of learning a second language

Question 30

Environmental Modification

Answer 30

heritable does not mean unmodifiable

eg: phenylketonuria, or PKU, a genetic inability to metabolize the amino acid phenylalanine; diet can change it

Question 31

Evolution

Answer 31

change over generations in the frequencies of various genes in a population

Question 32

Lamarckian evolution

Answer 32

if you exercise your arm muscles, your children will be born with bigger arm muscles, and if you fail to use your little toes, your children’s little toes will be smaller than yours

largely disproven

Question 33

fitness

Answer 33

operationally defined as the number of copies of one’s genes that endure in later generations

Question 34

Evolutionary psychology

Answer 34

evolutionary and functional explanations— that is, how our genes reflect those of our ancestors and why natural selection might have favored the genes that pro- mote certain behaviors

assumption is that any behavior characteristic of a species arose through natural selection and presumably provided some advantage, at least in ancestral times.

Question 35

altruistic behavior

Answer 35

an action that benefits someone other than the actor.

Question 36

kin selection

Answer 36

selection for a gene that benefits the individual’s relatives

Question 37

reciprocal altruism

Answer 37

idea that individuals help those who will return the favor

Question 38

group selection

Answer 38

altruistic groups thrive better than less cooperative ones

Question 39

alleles

Answer 39

pairs of genese that are aligned along chromosomes

Question 40

weight of the brain

Answer 40

 At birth, the human brain weighs approximately 350 grams

 By the first year, the brain weighs approximately 1000 grams

 The adult brain weighs 1200-1400 grams

Question 41

development of neurons

Answer 41

the following processes:

 Proliferation
 Migration
 Differentiation

 Myelination
 Synaptogenesis

Question 42

new neurons later in life

Answer 42

– Stem cells: undifferentiated cells found in the interior of the brain that generate “daughter cells” that can transform into glia or neurons

– New olfactory receptors also continually replace dying ones

– The hippocampus and basal ganglia

▪ Replace almost 2% neurons in hippocampus per year
▪ The newn eurons are invariably small interneurons, not neurons with long axons extending to other brain areas

Question 43

Brain in Adolescence

Answer 43

Synaptic density reaches adult levels at age 18

Immature connections between the limbic system, prefrontal cortex, and amygdala might produce “risky” behavior.

Increased activity in brain areas that anticipate reward likely why they are more risky

Question 44

Adult Brain

Answer 44

fully mature at age 25; weight of brain starts to decrease at age 45

Question 45

behavioral recovery after damage to brain

Answer 45

Mechanism:

– Increased brain stimulation

– Regrowth of axons

– Axon sprouting

– Denervation supersensivity

– Reorganized functional areas

Question 46

denervation supersensitivity or receptor supersen- sitivity

Answer 46

if a certain set of synapses becomes inactive—perhaps because of damage elsewhere in the brain—the remaining synapses become more responsive, more easily stimulated

helps compensate for de- creased input. However, when either collateral sprouting or denervation supersensitivity occurs, it can strengthen not only the desirable connections, but also undesirable ones, such as those responsible for pain