Genetics

Heredity and Genetics Gregor Mendel studied thousands of pea plants to up with the basic principles of heredity that we still use today

Heredity and Genetics These principles all start with sexual reproduction – where two prents combine sex cells (each with ½ of their DNA) to create new organisms - now with a combination of traits from each parent

Heredity and Genetics Chromosomes are coiled pieces of DNA and protein that carry genes (which code for a specific trait). Each form of a gene is called an allele. Alleles can be dominant or recessive.

Heredity and Genetics Dominant alleles will always present – or show (RR or Rr), while a recessive trait will only show itself if two recessive alleles are present (rr).

Heredity and Genetics An organism’s geneotype is represented by the letters – RR, Rr, or rr. The phenotype for these genotypes is either round or wrinkled.

Heredity and Genetics Reginald Punnett developed a tool called the Punnett Square – it is a way to predict all of the possible genotypes offspring could have. Each box in the Punnett Square shows a way the alleles from each parent could combine in potential offspring.