2. A trait is a notable feature or quality in a person. Each of us has a different combination or sets of traits that make us unique.
3. Traits are passed from generation to generation.
4. We inherit them from our parents and pass them eventually to our children.
5. Physical traits or characteristics of one's physical make up (how you look) observable characteristics determined by specific segments of DNA called genes.
6. Physical traits include things such as; hair color, eye color, earlobe attachment, handedness, straight hairline and widow's peak height.
7. Behavioral traits are characteristics of the way one acts. An example is a golden retrievers's instinct to retrieve.
8. A sheepdog's herding instinct is a good examples of behavioral trait.
9. Predisposition to a medical condition is another inheritable trait. Examples include sickle cell anemia, cystic fibrosis, and certain mental diseases.
10. The instructions encoded on our genes play a role in defining our traits.
11. However, the environmental influences in our lives are just as important in shaping our traits
12. Our genes determine our natural hair color, however, exposure to the sun and hair dyes can easily change the color.
13. Behavioral traits can be influenced by trainers, like raining dogs to chase things and bring them back.
14. A person may be born with a predisposition to heart disease, however a healthy diet and exercise can greatly reduce this risk.
15. How are traits determined? Try to bend your thumbs back at a 45 degree angle, if you can, you have "hitchhikers" thumb gene.
16. Other people don't have straight thumbs which don't bend.
17. Scientists describe a set of genetic information for each form as an allele. Most genes have two or more variations, called
alleles. For example, the gene for hairline shape has two alleles, that is; widow's
peak or straight. A person may inherit 2 identical (homozygous) or 2 different
(heterozygous) alleles from their parents.
18. We can describe the straight thumb allele with a H, and the hitchhikers thumb allele with a h. Capital H for the dominant alelle and the lower case for the recessive allele.
19. Each of us has two alleles that determine the thumb extension trait.
20. What two genotypes would code for straight fingers; These should be HH, (hmozygous dominant) and Hh (heterozygous).
21. The genotype that would code for the hitchhikers thumb is hh (homozygous recessive).
22. Having two of the same alleles for a trait is called homozygous.
23. Having two different alleles for a trait are called heterozygous
24. A person with a Hh genotype would have the straight finger phenotype.
25 The dominant allele (H) will mask or hide the recessive allele (h). This is known as the law of dominance. which is described such that In a cross of parents that are pure for contrasting traits, only one form of the trait will appear in the next generation. Offspring that are hybrid for a trait will have only the dominant trait in the phenotype
26. The chances of having a child with hitchhicker's thumb if both parents are hybrids is 1/4 or 0.5. A hybrid is a synonym for heterozygous; contains one dominant allele and one recessive allele
Using a punnet square as shown on the attached
