Inheritance
- 1. InherItance
- 2. Inheritance: the way genes are passed down. • If a father doesn’t have a leg does that mean his children will be born with out a leg????
- 3. Hundreds of years ago people knew that somehow certain traits would be passed on to their children.
- 4. Gregor Mendel was the first to predict the outcome of inheritance. The study of inheritance is Genetics.
- 5. • Mendel did several different experiments on pea plant. • This is an example of wrinkled and smooth seeds.
- 6. Genes and Alleles • A gene is a specific piece of DNA. • You have two genes that code for the same thing (ex. Height). Each of those two genes is called an allele. • So if something had the genes Aa one allele would be “A” the other would be “a”).
- 7. Why two alleles for every gene? • Because organisms get 2 sets of chromosomes ……….one from the mother and one from the father.
- 8. Phenotype • Is the physical characteristics of the trait. • In most cases it is what we can “see”. • Example: Freckles, dimples, attached earlobes etc.
- 9. Genotype • Is the actual alleles that make up the trait. • In most all cases this is represented by 2 letters. • Example: AA, Aa, aa
- 10. Dominant – A dominant trait is a trait that covers or hides the other trait of an allele. • For example, dark colors in hair usually overshadow the other allele. • In this class Dominant will always be represented with a capital letter. • Example: Say “D” is the allele for black hair and “d” is the allele for blond. The if an animal had Dd then it would have black hair.
- 11. Recessive • A recessive trait is the trait that is hidden by the dominant trait. • In an animal with Dd for hair color the recessive allele is “d”. • The animal carries a gene for blond hair but you can’t tell by looking at it.
- 12. Heterozygous • This is the term given two different alleles. • For example, Aa is heterozygous. • It may contain one gene for brown eyes(A) from the mother and one gene for blue(a) eyes from the father.
- 13. Homozygous • This is the term given to the two same alleles. • For example, AA or aa • A person may contain 2 genes for -brown eyes – one from each parent (AA) or 2 for blue (aa).