Download Genetics in Evolution

TRAITS
in a POPULATION
Humans have 46 chromosomes
•Chromosomes are DNA
•Sections of Chromosomes
(DNA) are genes
•Your DNA Genes give you
specific traits (tall, short,
Red hair
blond, brown)
Chromosome 16
• MC1R is the gene for
proteins involved in
regulating mammalian skin and
hair color.
• MC1R is an ALLELE.
• it is sometimes called the
‘Ginger Gene’. It is the
Red hair
ALLELE for Red hair
This gene is actually rare
Allele : version of a gene that produces a trait
Alleles are genetic differences of a specific gene
Different Alleles (traits) can be from
mutations
Certain Alleles (genes) variations are more common than
others naturally. They arise from mutations in DNA
Alleles: are genetic differences of a specific
gene
A couple working definitions
• Evolution – Observable change over a long
period of time.
• Fitness – The ability to survive and reproduce.
• Gene pool – Combined collection of all alleles
(traits) in a population.
• Allele frequency – Overall amount of an allele
(trait) in a population.
Evolution without selection
• GENETIC DRIFT: occurs when a population is small. An allele (trait) frequency
(how many there are) may be changed by accident with no pressure from the
environment
Founder Effect
Blonde hair Solomon Islands