DNA and Selective Breeding

1. DNA and Selective Breeding

2. DNA • Known for it’s twisted ladder like appearance. • Sides of the ladder are made up of sugars called Deoxyribose and Phosphates • Each rung is made up of molecules called nitrogen bases. • 4 bases only, they are always in certain pairs

3. Nitrogen Bases The 4 bases are: • Adenine = represented by the letter A • Thymine = represented by the letter T • Guanine = represented by the letter G • Cytosine = represented by the letter C • A is always paired with T • G is always paired with C • If you had only 1/2 the ladder, could you tell what the whole would look like? Why?, Why not?

5. How DNA replicates • Replication begins during interphase • Step 1: the two sides unwind and separate like a zipper • Step 2: The nitrogen bases [A, T, G, C] floating in the nucleus pair up with the bases on each exposed half This is what makes it possible for exact copies to be made *** Remember Adenine only pairs with Thymine Guanine only pairs with cytosine

6. dna brainpop

7. Selective Breeding • Knowing what we know about genetics and how traits are passed, scientists used that information to produce offspring with specific traits. Think back to Mendel and his pea plants • Selective breeding is simply being picky/selective about which parents reproduce • This process is commonly done with animals and plants. • What different plants and animals do you think have been bred for a specific purpose or for a specific look?

9. Reasons for selective breeding Most species of animals, when they reproduce only will with strong partners who will produce strong children, more chances for survival Plants are selectively bred for certain traits like taste, speed of growth, hardiness, and usefulness. They can also be bred for healthy eating or for looks Humans do a lot of selective breeding with vegetables like the colorful cauliflower and many animals. Most dog breeds are selectively bred for different purposes and looks.