1. BioEd Online Genetics and Genomics Why Do I Look Like I Do? Dr. Ron McNeel

2. www.BioEdOnline.org BioEd Online We’re the Same The human species has similar characteristics Name a few Characteristics are called TRAITS

3. www.BioEdOnline.org BioEd Online But We are also Different Humans can have different forms of the same trait Name some different forms of the same trait

4. www.BioEdOnline.org BioEd Online These different forms of traits are called Variations

5. www.BioEdOnline.org BioEd Online But Wait!! Families are Similar

6. www.BioEdOnline.org BioEd Online Sometimes Identical

7. www.BioEdOnline.org BioEd Online Start in the Cell Nucleus Nucleus Coordinates the Cell Processes Contains the Genetic Information that makes you Your genome

8. www.BioEdOnline.org BioEd Online Part of the Genome is Divided into chromosomes Long arm Short arm Centromere

9. www.BioEdOnline.org BioEd Online Chromosomes have similarities and differences Similarities Only found in the nucleus Normally, humans have 46 chromosomes All packaged the same way Differences 44 chromosomes NOT involved in determining sex of individual Called Autosomes What do you think the other two chromosomes are called?

10. www.BioEdOnline.org BioEd Online Differences Sex Chromosomes X & Y Chromosomes Determines Sex

11. www.BioEdOnline.org BioEd Online Other Differences Chromosomes have Different Lengths Physical Appearance Centromeres

12. www.BioEdOnline.org BioEd Online Autosome Surprise Each autosome has a “partner” How many autosomes are there? 44 How many partner pairs are there? 22 pairs See them?

13. www.BioEdOnline.org BioEd Online Finding the Autosomal “Partners” Difficult to find them easy like this Putting numbers on them doesn’t help much Any ideas to help find the “partners”?

14. www.BioEdOnline.org BioEd Online Sorting Out the Autosomes What if we arrange the “partners” based on their lengths? What is this called? karyotype

15. www.BioEdOnline.org BioEd Online

16. www.BioEdOnline.org BioEd Online Where does each partner come from?

17. www.BioEdOnline.org BioEd Online Where does each partner come from? One from your mother One from your father

18. www.BioEdOnline.org BioEd Online What About the Sex Chromosomes (X and Y)? One from your mother One from your father

19. www.BioEdOnline.org BioEd Online Which Sex Chromosome can the Mother Contribute? X Chromosome ONLY!

20. www.BioEdOnline.org BioEd Online X or Y Chromosome Who determines the sex of the offspring? MALE

21. www.BioEdOnline.org BioEd Online Review What percentage of your chromosomes comes from each parent? 50% How many autosomes from each parent? 22 How many sex chromosomes from each parent? 1

22. www.BioEdOnline.org BioEd Online Hey, wait a second! How many total chromosomes in human female cell nucleus? How many chromosomes in human male cell nucleus? Then matting would produce… Why does this not happen? 46 46 92 chromosomes in offspring 92 92 184 chromosomes in offspring

23. www.BioEdOnline.org BioEd Online ANSWER: Special Cells - Gametes Female Egg Male Sperm

24. www.BioEdOnline.org BioEd Online Gametes Formed by a Special Type of Cell Division Meiosis (reduction division) found only in reproductive cells (gametes)

25. www.BioEdOnline.org BioEd Online We Must Divide to Multiply Meiosis – reduction division Gametes have half the number of chromosomes Female 46  23 in egg Male 46  23 in sperm 46 in offspring

26. www.BioEdOnline.org BioEd Online During Fertilization 23 chromosomes from your mother 23 chromosomes from your father 46 chromosomes in offspring Life is good again!

27. www.BioEdOnline.org BioEd Online Closer Look at Chromosomes Chromosomes are long molecules of deoxyribonucleic acid (DNA)

28. www.BioEdOnline.org BioEd Online Closer Look at Chromosomes

29. www.BioEdOnline.org BioEd Online DNA Packaging Your genomes has 3 billion base pairs (every cell) Typist 360 letters/minute for 8 hours a day copy your genome in 50 years If recited the genome at 1 letter per second 24/7 it would take 100 years to finish

30. www.BioEdOnline.org BioEd Online DNA Packaging If the DNA from ONE cell was stretched out: It’d be from 6-9 feet in length If stretched the DNA from every cell and placed end to end It would reach to the sun and back over 600 times

31. www.BioEdOnline.org BioEd Online DNA Contains Genes Gene = DNA segment that contains the code to make a particular protein Proteins determine your characteristics or traits

32. www.BioEdOnline.org BioEd Online DNA → Protein → Trait Trait = Physical appearance or Phenotype Red hair Brown eyes Sickle cell Albinism

33. www.BioEdOnline.org BioEd Online Summing it Up Chromosomes → DNA DNA → Genes Genes → Proteins Proteins → Make you, YOU Francis Crick - “DNA makes protein, and protein makes us”