Intro to Heredity & Genetics Heredity and Genetics Future Technology

Plant Cell Division Plants are complex organisms that grow throughout their lifetime. Cells inside these organisms divide in two ways for two different purposes Mitosis: body cell use Meiosis: reproductive cells use

Plant Cell Division: Mitosis Body cells use to reproduce Nucleus divides and forms new identical cells.

Plant Cell Division: Meiosis Reproductive cells (gametes) – go through meiosis. Nucleus divides twice and you end up with 4 new cells – each with ½ of the genetic material as the parent cell.

Selective breeding Allows farmers to select and breed two parent plants to produce offspring with the traits they choose. Examples include sweeter corn, bigger tomatoes and round peas.

Genetic engineering Allows farmers to get the traits they want, by taking a section of DNA from one organism and inserting it into another organism Example: glow in the dark tobacco plant

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 parents combine 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).

Genotype An organism’s genotype is represented by the letters – RR, Rr, or rr. The phenotype for these genotypes is what the trait means (red hair, long nose). Homogeneous genotype: no mixing, the sale alleles RR tt rr TT Heterogeneous genotype: mixing of alleles Rr Ss Qq

Punnett Square Created by Reginald Punnett Predicts 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.