1. Genetics 101 Welcome to everything you wanted to know about Genetics!

2. Genetics…  is the study of genes, heredity, and variation among living organisms.  It is studied through biology.

3. Remember…  Traits vary in a population…this is the key to species survival!  Offspring resemble their parents and this is from the passing of genetic information.

4. Gregor Mendel  Conducted pioneering work with inheritance.  Most important work was done with pea plants…he studied the trait of flower color.  He realized that plants did not combine colors (i.e. purple + white did not give a pale lavender color, but the plant was either white or purple). Why?  The answer…genes!

6. Animal Cell  Every living thing is made of cells.  Cells have organelles and one organelle is the nucleus (center part of a cell).  Inside the nucleus is DNA.  DNA = deoxyribonucleic acid; an inheritance messenger; a huge molecule containing millions of atoms; DNA is coiled into chromosomes in the nucleus in cells  Chromosomes = structures that carry the message of inheritance (DNA)

9. Nucleus, Chromosomes, and DNA

11. DNA Contains a Code!!  Four Bases  Adenine (A)  Guanine (G)  Cytosine (C)  Thymine (T)  A pairs with T  G pairs with C  The sequence and number of these bases determines the trait (e.g. AATGCTTAA might be the sequence at a specific point in the DNA strand for brown hair).  DNA is HUGE….roughly 3 billion base pairs or “rungs” and nearly 25,000 genes!!!!

12. Why DNA Matters!  You have the full DNA strand in each cell of your body.  Only part of your DNA strand is used in certain types of cells (e.g. skin cells only code for your skin and just use that part of the DNA strand needed).  Reproductive DNA is what gets passed on to your offspring!

13. Alleles  allele = specific active location on a chromosome

14. Genes  Gene = two alleles on the paired chromosome working together; a pair of alleles!

15. Big Ideas!  1. Nuclei contain chromosomes.  2. Chromosomes come in almost identical pairs.  3. Chromosomes have specific active locations called alleles.  4. The two alleles in identical locations on paired chromosomes constitute a gene.  5. A gene (two alleles working together) controls a trait.

16. Genotype  Genotype = combination of alleles in an organism’s chromosomes  AA, Aa, or aa, are all genotypes.

17. Phenotype  1. Phenotype = what trait is expressed in an organism  2. It’s what they look like!  3. The traits that the genotype produce is the organism’s phenotype!  Examples: AA or Aa would produce brown eyes  aa would produce blue eyes

18. Dominant  Dominant Alleles = more influential alleles; represented by an uppercase letter  AA or Aa  Brown eyes are a dominant trait.

19. Recessive  Recessive Alleles = less influential alleles; represented by a lowercase letter  Aa or aa  Examples: blonde or red hair, blue or green eyes

20. Types of Genotypes  Homozygous – When the alleles in the genotype are the same (e.g. AA, aa). Also called purebred.  Homozygous dominant would be: AA  Homozygous recessive would be: aa  Heterozygous – When the alleles in the genotype are different (e.g. Aa). Also called hybrid.

21. Reproduction and Chromosomes  Chromosome pairs will split and exchange part of the genetic material so that half the genetic material comes from one parent and the other half of the genetic material comes from the other parent.  This adds variation to the offspring  It also leads to…

22. Inheritance  Passing genetic information from one generation to the next. Offspring inherit alleles from their parents.

23. From Genotype to Phenotype!  Decode the genotype to produce the Larkey’s phenotype!

24. Chromosomes, Genes, and Alleles  A Chromosome is a concentrated DNA strand and they usually come in pairs.  Genes are genetic material on a chromosome that code for a trait. For example, you have a gene for eye color and that gene is in a specific location on the chromosome (or in the DNA strand).chromosome  Alleles are variations of genes. For example, you may have the alleles for brown eye color on the locus for the eye color gene.