What is Genetics? Genetics also provides us with tools to produce improved crops and livestock (we ve been doing this for thousands of years).

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1 What is Genetics? Genetics is the study of heredity (how characteristics are inherited from generation to generation) and of variation (why individuals of a species are different from each other). Why is Genetics important? Genetics allows us to understand normal events such as development, growth and ageing in terms of the underlying molecular machinery that direct these processes, and provides an understanding of why these processes go wrong in disease. Genetics also provides us with tools to produce improved crops and livestock (we ve been doing this for thousands of years). We share about... 98% of our genes with an ape 80% of our genes with a mouse 50% of our genes with a fruitfly 20% of our genes with a tiny worm What is Genetics? The main ideas looked at in genetics are... The genetic code (DNA / genes) How the genetic code is passed on (probability) How the genetic code is expressed (gene expression) 1

2 Gene Expression Cell specializes using specific genes What is Genetics? DNA (DeoxyriboNucleic Acid) is the chemical that carries genetic instructions for making all the traits found in living things. DNA is made of two long, twisting strands called a "double helix". Genes are recipes for individual proteins that make up traits that we can inherit from our parents. Chromosomes are sets of genes (DNA) that are packaged up into units like books in a library. Humans have 23 pairs (46 total) of chromosomes. One member of each pair is inherited from the mother, and the other from the father. A genome is an entire system of genes that makes up a species. Genomics is the study of how genes interact and influence the biology and physical characteristics of living things. 2

3 Levels of Genetics Information How the genetic code is passed on? Parents pass on half of their genetic materials to their offspring in the form of chromosomes through their egg or sperm in a process called mating. This means that there is a degree of random probability involved in determining which traits you may get from each parent. The expected frequency of a particular event when an experiment is repeated an infinite number of times is the probability of the event. For a single coin toss, the probability of a head on a single toss is 1/2. 3

4 How much do you know? Answer TRUE or FALSE to the following questions If two parents have brown eyes, then all of their children will have brown eyes. 2. If your father or mother is a diabetic, you could also be a diabetic. 3. If a mother eats strawberries before her child is born, the child will have a strawberry birthmark. 4. A man s sperm cells determine whether a child will be a boy or a girl. 5. No one has ever seen a chromosome. 6. Some of our inherited traits are influenced by the environment. 7. Persons of the same sex can donate blood to others of the same sex even if blood types are different. 8. Each parent gives an equal number of chromosomes to his or her children. 9. Only the father s traits show in a male child. 10. A person can be born with one brown eye and one blue eye. 11. Identical twins are always of the same sex. 12. Fraternal twins are more closely related to each other than to other children in the family. 13. Colour blindness is more common in males than females. 14. A parent can pass traits to a child even though the parent does not show the trait. 15. All harmful traits are caused by recessive traits. 16. Identical twins have more of the same genes than other children in the family. 17. The tendency for twins in a family is inherited. 18. Some traits do not show in a person because the traits are recessive. 19. A child inherits temper from its parents. 20. None of the grandparents traits are passed on to the grandchildren. Genetics Terms Alleles are alternate forms for genes (which come from the mother or the father from the gametes [sperm or egg ] ). Humans have 2 alleles per trait. Dominant Allele is an allele that is fully expressed and is symbolized by a capital letter. (Often the first letter of the word for which the trait stands for) Recessive Allele is an allele that is completely masked and symbolized by the SAME letter, but it is a lower case letter B = blue colour gene Dominant Allele b = red colour gene Recessive Allele 4

5 Humans have 2 alleles per trait (one allele from the mother, one from the father) For dominant and recessive traits what would be the trait that you see for the following... BB Bb B = blue colour gene Dominant Allele b = red colour gene Recessive Allele bb 5

6 In this assignment, are to create a new creature (a new type of animal species) called a Reebop. You are a Reebop parent, and with another Reebop parent you will create 2 Reebop baboes! Part A: Pick 8 traits that have a dominant allele and a recessive allele Traits can involve things like colours and styles of body parts. 6

7 Part B: Make Offspring by flipping coins (Heads=Dominant Allelle & Tails = recessive allele) Record your outcomes here Baby #1: Baby #2: Part C: Draw a picture of the Offspring Draw a picture of baby #1 and baby #2 correctly illustrating all the the traits determined by the coin tosses. 7