1. Meet Baby Blue Eyes.

2. We’ve seen a black child with blue eyes before.

3. However, this boy’s eyes are not a mutation
However, this boy’s eyes are not a mutation. He inherited the trait from his parents – both of whom have brown eyes.
Mom
Dad

5. Another mystery we will tackle…

6. And another…

7. And another…

8. All of these questions – and many more – can be answered by studying genetics.

9. Genetics
The scientific study of inheritance. I

10. In genetics, parents pass genes to their offspring.

11. Gene
Fur color gene
A segment of DNA that contains the instructions for making one specific protein. S D I P

12. DNA: instructions for all proteins Gene: instructions for one protein
Eye color
Tail length
Fur color
Blood type

13. Nucleus
DNA
Cell
Chromosome
Gene
Nucleotides

14. Genes are passed from parent to offspring through the gametes (sex cells).

15. Genes are “packaged” inside gametes.

16. Gametes combine during the process of fertilization.

17. Since 2 gametes combine during fertilization, offspring receive 2copies of each gene.
Egg
Sperm
Gene
Gene
Gene
Offspring
Gene

18. Trait: eye color
Blue
Blue
Blue
Blue

19. Trait: eye color
Brown
Blue
Brown
Blue

20. The three people below all have the eye color gene, but they have different alleles for that gene.
Brown C G A C G T A T G
Eye color gene T A G C A G T T G
Blue A T C G T C A A C
Eye color gene C G A G C T C T A
Green G C T C G A G A T

21. Alleles G C T G C A T A C T A G C A G T T G C G A C G T A T G A T C G
Fur color gene
Fur color gene G C T G C A T A C T A G C A G T T G
Black
Tan C G A C G T A T G A T C G T C A A C
Fur color gene C G A G C T C T A
Gray G C T C G A G A T
Different versions of a gene caused by different sequences of nucleotides, resulting in slightly different proteins. V G N P

22. Ex: for the eye color gene, brown, black, green, blue, and purple are alleles.

23. Do these roses have different genes, or different alleles?
Both have the petal color gene
They have different alleles (red, yellow)

24. Different genes, or different alleles?

25. Gene: hair color Alleles:
The word “gene” is more general. The word “allele” is more specific. G S
Gene: hair color
Dark brown
Dark red
Light red
Brown-black
Alleles:
Blonde
Auburn
Black

26. C A T G A T G G A T G U A C U A C C U A
New alleles are produced by mutation. M C A T G A T G G A T G U A C U A C C U A
Val
Tyr
His
Leu

27. When parents with different alleles produce offspring, the offspring is known as a hybrid.

28. Hybrid The offspring of parents with different alleles. Curly allele
Straight allele
The offspring of parents with different alleles. O P A

29. Alleles may blend in a hybrid, or one allele may be stronger than another.
BROWN
HAZEL