Transcript Mendel`s Laws of Heredity

Mendel’s Laws of
Heredity
Why we look the way
we look...
Mendel used peas...
They
reproduce sexually
They have two distinct,
male and female, sex cells
called gametes
Their traits are easy to
isolate
Mendel crossed them
Fertilization
- the uniting
of male and female
gametes
Cross - combining gametes
from parents with
different traits
What Did Mendel Find?
He
discovered different
laws and rules that explain
factors affecting heredity.
Rule of Dominance
The
trait that is observed
in the offspring is the
dominant trait (uppercase)
The trait that disappears
in the offspring is the
recessive trait (lowercase)
Law of Segregation
 Genes
appear in pairs on
homologous chromosomes
 SEPARATED when gametes are
formed
 Recombine during fertilization
Law of Independent
Assortment
 The
genes for different traits are
inherited independently of each
other.
 Homologous chromosomes move
randomly to gametes
 Explains why siblings look different
Monohybrid Vs Dihybrid
Monohybrid
Cross - crossing
parents who differ in only one
trait (AA with aa)
Dihybrid Cross - crossing
parents who differ in two
traits (AAEE with aaee)
Bozeman Tutorial
http://www.youtube.com/watch?v=Y1P
CwxUDTl8
Incomplete Dominance - Blend
Codominance - Both show
Sex-Linked
Sex-Linked
Multiple Alleles - Blood Type
Multiple Alleles - Blood Type
Dihybrid Cross - 2 traits