Chapter 4

Question 1

Mendel:

Answer 1

19th century, believed inheritance occurs through genes
○ Plant hybridization= foundation of modern genetics
○ Early writer on evolution

Question 2

gene

Answer 2

most basic unit of heredity
○ Like pieces of DNA
○ Humans have around 20,000

Question 3

Chromosomes

Answer 3

strands of genes, normally in pairs

Question 4

Genotype

Answer 4

notation of gene pair (BB, Bb, bb)

Question 5

Phenotype

Answer 5

expression of a gene

Question 6

Sex-linked genes

Answer 6

23rd pair (sex chromosomes)

Question 7

Sex-Limited genes

Answer 7

on other 22 pairs (autosomes)

Question 8

Sex-Limited genes

Answer 8

○ In both sexes, but effect mostly limited to one sex
■ Both males and females possess the genes
○ Male pattern baldness is sex- limited
○ Genes “turned on” by androgens
■ DHT receptor in hair follicle
○ Taking hormones will alter how genes are expressed

Question 9

Nature vs Nurture

Answer 9

● Recent studies indicate false dichotomy
● Enviro can affect appearance (flamingos)

Question 10

Epigenetics

Answer 10

: phenotype changes with no DNA sequence change, heritable, genes
turned on/off for generations