Unit 1 Scientific Approaches

Chapter 4

Genes and heredity

Basic Genetics

• 1.Genes are in pairs (alleles), one from each parent

• 2.dominant or recessive, homozygous or hetero

• 3.Genes segregate (separate) during reproduction

• 4.Genes assort independently, combos are random

• Genotype- genetic makeup, genes

• Phenotype- what it physically looks like

• Polygenetic traits- come from combo of many genes

• Ex: nose shape, hair color

DNA

• Genes located on chromosomes

• Some are sex linked (carried on X)

• Central Dogma• DNA --> RNA -->

Protein

• Haploid + Haploid= Diploid

• N + N = 2N• 23 from mom + 23

from dad = 46 baby

What Genes Do

Control body processes

Are not expressed all the time

Heritability:

Behavior= Genetics + Environment

Genetic Mutation and Evolution

• 1. Mutations- random change in genes, lead to new phys or beh traits

• 2. Gene flow- mov’t of indiv in or out of pop which changes allele frequency

• 3. Genetic drift- changes in gene pool by chance (environment changes, disease, etc)

• 4. Nonrandom mating- sex selection

Genes and Behavior

• Different genes lead to

• Different proteins and amino acids which lead to

• Different behavioral traits

Selection

• Artificial selection- selective breeding for certain traits

• Making hybrids to combine breed traits

• Instinctive drift- behavior gravitates toward strong instinctive pattern even when learning or training contradicts it