Download introduction to genetics

INTRODUCTION TO
GENETICS

The science of
inheritance

Parents and
offspring

heredity is the set
of characteristics
an organism
receives from his
parents
INTRODUCTION TO
GENETICS
INTRODUCTION TO
GENETICS

Gregor Mendel
 worked with peas
 discovered 7 traits
in true breeding pea
plants
 F1 generation
 F2 generation
INTRODUCTION TO
GENETICS

Gene functional unit
that controls inherited
trait expression that is
passed on from one
generation to the next
 Dominant allele a
specific trait that
appears in the F1
generation
 Denoted with a capital
letter
INTRODUCTION TO
GENETICS


Recessive allele a
specific trait that is
masked in the F1
generation
 Denoted with a
small letter
Homozygous
organism with two of
the same alleles for a
specific trait
INTRODUCTION TO
GENETICS
 Heterozygous
organism with two
different alleles for a
specific trait
 Hybrid organism
heterozygous for a
specific trait
INTRODUCTION TO
GENETICS
INTRODUCTION TO
GENETICS

Segregation
 A process that
separates the
two alleles
 Independent
assortment
INTRODUCTION TO
GENETICS
 Mendel’s principles
 individual units, called genes,
determine biological characteristics
 For each gene, an organism
receives one allele from each
parent.
INTRODUCTION TO
GENETICS


if an organism inherits different alleles
for the same trait, one allele may be
dominant over the other
some genes segregate independently
INTRODUCTION TO
GENETICS
 TURN AND TALK Explain
dominance, segregation, and
independent assortment.
INTRODUCTION TO
GENETICS

Meiosis
 Chromosomes
 Forming gametes
 haploid and diploid cells
 Haploid having one copy of
each chromosome
 Diploid having two copies of
each chromosome
INTRODUCTION TO
GENETICS

Phases of meiosis
 Have students reproduce chart on pg
133 of book.
 Meiosis and genetic diversity
 chromosome combinations (pg 134 in
book)
INTRODUCTION TO
GENETICS
 Crossing over
exchange of
chromosomal
segments between
a pair of
homologous
chromosomes
during prophase I
INTRODUCTION TO
GENETICS
 TURN AND TALK Explain how
crossing over increases genetic
diversity.
INTRODUCTION TO
GENETICS

Analyzing
inheritance
 Probability
 Probability and
genetics

INTRODUCTION TO
GENETICS
A closer look at heredity

Incomplete
dominance complex
heritance pattern in
which the
heterozygous
phenotype is
intermediate between
two heterozygous
parents
INTRODUCTION TO
GENETICS

Co-dominance
complex inheritance
pattern that occurs
when neither allele
is dominant and
both alleles are
expressed
INTRODUCTION TO
GENETICS
 Polygenic traits
characteristic,
such as eye color
or skin color, that
results from the
interaction of
multiple gene pairs