Download Name - Georgetown ISD

Name
Period
Heredity
Genetics
Learning Goal: I will …
- predict possible outcomes of various genetic combinations such as
monohybrid crosses
Inheritance
 Heredity is the passing of characteristics from parents to offspring.
 Genetics is the study of heredity or how those traits are inherited.
 Gregor Mendel is known as the Father of Genetics.
Carrying out a cross
 Sex cells are called gametes
 Uniting of male and female gametes is fertilization
Phenotype
Genotype
Allele
Dominant
Recessive
Homozygous
Heterozygous
Monohybrid
Dihybrid
Test cross
Law of
Segregation
Law of
Independent
Assortment
Punnett Square
Genetics terminology
 Phenotype is the physical characteristic – what it looks like
 Genotype is the actual combination of alleles
 Allele is the different forms of a gene
 Dominant – trait that covers the recessive trait (T)
 Recessive – trait that gets covered up (t)
 Homozygous – two alleles are the same
Homozygous dominant – both alleles are dominant (TT)
Homozygous recessive – both alleles are recessive (tt)
 Heterozygous – two different alleles (Tt)
Crossing Traits
 A monohybrid cross looks at only 1 trait
 A dihybrid cross looks at the inheritance of 2 traits
 A test cross reveals an unknown genotype by breeding it with a
homozygous recessive individual
Mendel’s Laws of Inheritance
 Law of Segregation: the two alleles will segregate (separate) into
different gametes
 Law of Independent Assortment: each trait is inherited
independently from each other
Monohybrid Cross Punnett Squares
BB x bb
Bb x Bb
Bb x bb
Summary Word Bank

Alleles

Dominant

Genotypes

Homozygous
recessive

Punnett
Summary of Learning
A Punnett square can be used to predict inheritance of different alleles.
Phenotypes can be determined from genotypes. For example, an
individual with a heterozygous genotype or a homozygous dominant
genotype will express a dominant phenotype. An individual with a
homozygous recessive genotype will express the recessive phenotype.
predict possible outcomes of various genetic combinations such as monohybrid crosses,
dihybrid crosses and non-Mendelian inheritance