FERTILIZATIONFERTILIZATION& &
Intro to Mendelian GeneticsIntro to Mendelian Genetics
In vitro Fertilization
http://www.youtube.com/watch?v=FXeGivCzdDs
EMBRYO DEVELOPMENT
TWINS
Mendel and His Peas
Results
Tall x Tall
F1 offspring #3 X F1 offspring # 3 Tall Tall
Conclusion?
Short x Short
Tall x Short
Conclusion?
Conclusions• Every characteristic or trait (e.g. height) is
determined by two factors (alleles). • There are variations in alleles (e.g. height= tall
(T) or short (t))• Genotype: What combination of alleles an
individual has (TT, Tt, tt)• Homozygous: individual has two of the same
alleles (TT, tt)• Heterozygous: individuals have two different
alleles (Tt)
• Phenotype: What the individual physically looks like (determined by genotype)
• Dominant allele: The allele that shows up physically in the heterozygous form
• Recessive allele: The allele that is not displayed physically in the heterozygous form
Is Dominant the most common allele in the population?
Genotype Phenotype
Homozygous Tall TT Tall
Heterozygous Tall
Tt Tall
Homozygous Short
tt Short
Mendel’s Law of Segregation
• Each allele separates into different gametes during meiosis therefore only one allele is passed down to the offspring
T
t
T t T Tt t T
t
meiosis
DNA replication
Explaining Mendel’s Observations