1. Introduction to Genetics Ms. Lazzaro

2. Heredity ► passing characteristics from parent to offspring (children) ► Fertilization-male and female gametes combine to form new offspring ► Pollination – (in plants) pollen grains fertilize female gamete

3. Genetics ► study of heredity

4. Gregor Mendel ► in charge of monastery garden, ► Father of genetics ► studied characteristics of peas and how characteristics are passed on ► Normally peas self –pollinate = males fertilize female’s egg of same flower ► He would cause cross-polination = offspring (seeds) of 2 different parents ► Studied 7 characteristics – study a few or else too many

5. Mendel’s Findings ► Due to his observations, Mendel decided that there must be two factors controlling each trait. He concluded that there was a dominant (A) and a recessive (a) form of each trait and that presence of the dominant form masked the recessive form. Each of these forms is now called an allele. ► Mendel’s law of segregation says that a pair of factors is separated or segregated during the formation of gametes (meiosis). ► Mendel’s law of independent assortment says that factors for different traits are distributed to gametes independently from one another.

7. Trait ► Characteristic ► example: eye color or hair color or height

8. Genes ► Factors or piece of DNA that determines a characteristic ► for example a piece of DNA codes for a protein or product which determines these characteristics

9. Alleles ► different forms or versions of a gene ► Example: blue, brown, green eye color ► Example: Gene: height; alleles = tall short; ► Organisms have 2 alleles for each gene (1 on each chromosome) ► Gametes have 1 allele because haploid ► Let Y = yellow and y = green since same gene & (only 2 alleles) lets use the same letter

10. Dominant ► seen even if other versions are present ex: Yy and YY both appear yellow no blending ► designated with a capital letter ► usually more common but not always ► NOT seen if other versions are present ► Only if homozygous recessive yy ► designated with a lower case letter Recessive

11. Geneotype ► Genetic make-up ► the alleles you have ► Homozygous = have the same alleles for a particular gene example: YY or yy ► Heterozygous = have different alleles for a particular gene example: Yy

12. Pheneotype ► Physical appearance ► characteristics we see ► If YY or Yy = appears yellow (so phenotype = yellow) ► If yy = green ► Why is Yy yellow not green?