1. Genetics Review

2. A segment of DNA
What is a gene?

3. They carry genetic information from generation to generation.
What does a gene do?

4. Sex-chromosomes (X and Y)
What determines the gender of an individual?

5. What is this diagram above called?
A karyotype
What is this diagram above called?

6. Is this karyotype from a male or female?

7. Which pair of chromosomes are the sex chromosomes?
The 23rd pair (XY)
Which pair of chromosomes are the sex chromosomes?

8. Autosomal Chromosomes
What are the first 22 pairs or chromosomes called?

9. Homozygous Dominant
In pea plants Tall (T) is dominant to short (t). In genetics terms, a pea plant with the following genotype, (TT), is considered?

10. The genetic make-up of an organism.
Define genotype.

11. A cross between two true-breeding parents is called?
A hybrid
A cross between two true-breeding parents is called?

12. Both heterozygous (Tt)
In pea plants Tall (T) is dominant to short (t). A cross between two tall plants of unknown genotype results in a 75% tall and 25% short offspring. What are the genotypes of the parents?

13. Name the Monk who first performed scientific studies of genetics.
Gregor Mendel
Name the Monk who first performed scientific studies of genetics.

14. Alleles
What are the alternative forms of a gene that control the same trait called?

15. would result in what phenotype(s)?
All long tailed rats.
In rats a long tail (L) is dominant to a short tail (l). A cross between:
LL X Ll
would result in what phenotype(s)?

16. Intermediate inheritance/Incomplete dominance
A cross of between Green frogs (CGCG) and Yellow frogs (CYCY) produces all Blue frogs (CGCY). This type of inheritance is called?

17. Short, yellow seed
A dihybrid cross between heterozygous individuals (TtYy X TtYy) for two traits produces the following offspring. Tall (T) is dominant to short (t) and Yellow (Y) is dominant to green (y), What phenotype is a (ttYy) offspring

18. Tall, yellow seed
A dihybrid cross between heterozygous individuals (TtYy X TtYy) for two traits produces the following offspring. Tall (T) is dominant to short (t) and Yellow (Y) is dominant to green (y), What phenotype is a (TtYy) offspring

19. Short, green seed
A dihybrid cross between heterozygous individuals (TtYy X TtYy) for two traits produces the following offspring. Tall (T) is dominant to short (t) and Yellow (Y) is dominant to green (y), What phenotype is a (ttyy) offspring

20. Tall, yellow seed
A dihybrid cross between heterozygous individuals (TtYy X TtYy) for two traits produces the following offspring. Tall (T) is dominant to short (t) and Yellow (Y) is dominant to green (y), What phenotype is a (TTYY) offspring

21. 9:3:3:1 ratio
A cross between two individuals that are heterozygous for 2 traits (XxXx) would result in what phenotypic ratio?

22. Homozygous Recessive
In pea plants Tall (T) is dominant to short (t). In genetics terms, a pea plant with the following genotype, (tt), is considered?

23. Short tailed, black rat.
In rats long tails (L) are dominant to short tails (l), and black hair (B) is dominant to red hair (b). A cross between LlBb X LlBb results in numerous offspring. One has a genotype of llBb. What does this rat look like?

24. The heterozygous offspring that result from a cross between 2 true-breeding parents.
XX x xx = Xx
Define hybrid.

25. Red is dominant to white and a cross between (RR X rr) results in all (Rr) offspring.
Red flowers (R) are dominant to white (r) flowers. A cross between two true-breeding parents (Red and White) results in all red flowers, why?

26. Homozygous recessive (rr)
Red flowers (R) are dominant to white (r) flowers. In order to express the white flower trait what must the genotype be?

27. What three pieces of information can be gained from a Punnett square?
All possible offspring
All possible genotypes of offspring
The alleles of the parents
What three pieces of information can be gained from a Punnett square?

28. The heterozygous offspring that result from a cross between 2 true-breeding parents that are homozygous for 2 traits.
XXTT x xxtt = XxTt
Define dihybrid.

29. It carries genetic information from generation to generation.
What does a gene do?

30. ½ or 50%
After flipping a coin 1000 times, what is the chance of the next flip being tails?

31. 1/6
When rolling a single dice what is the chance of rolling any particular number?

32. The way an organism looks as a result of their genotype.
Define phenotype.

33. Round seeds (S) are dominant to wrinkled seeds (s).
100%
Round seeds (S) are dominant to wrinkled seeds (s).
Two true-breeding plants for each trait are crossed. The probability that the F1 offspring will have round seeds is?

34. The gene for colorblindness is carried on the X chromosome
The gene for colorblindness is carried on the X chromosome. Men only need 1 allele to express the trait because they only have 1 X chromosome.
Colorblindness is a sex-linked disorder. Why is this disorder more common in males?

35. What is this diagram called?
A pedigree
What is this diagram called?

36. When a plant fertilizes itself the process is called?
Self-pollination
When a plant fertilizes itself the process is called?

37. 50%
If a couple have three girls, what is the chance that their fourth child will be a boy?

38. Alleles separate during gamete formation. Mendel called this?
The law of segregation.
Alleles separate during gamete formation. Mendel called this?

39. List all possible gametes from the following genotype (SS)

40. List all possible gametes from the following genotype (Ss)

41. List all possible gametes from the following genotype (SSTT)

42. When two different plants fertilize each other it is called?
Cross-pollination
When two different plants fertilize each other it is called?

43. List all possible gametes from the following genotype (SsTT)
(ST), (sT)
List all possible gametes from the following genotype (SsTT)

44. List all possible gametes from the following genotype (SsTt)
(ST), (St), (sT), (st)
List all possible gametes from the following genotype (SsTt)

45. Polygenetic Inheritance
Variations in human traits, such as height or skin color are examples of what type of inheritance?

46. A test cross.
A dominant phenotype of unknown genotype is crossed with a homozygous recessive genotype. What is this type of cross called?

47. XX
A test cross results in offspring with only the dominant phenotype. What was the genotype of the unknown parent, XX or Xx?

48. Xx
A test cross results in offspring with 50 % dominant phenotype. What was the genotype of the unknown parent, XX or Xx?

49. XBY
Colorblindness is an X-linked recessive trait. The shaded figures in the pedigree represent individuals who are colorblind. (B) represents the allele for normal color vision, and (b) represents the allele for colorblindness. What would Tom’s genotype be?

50. XbXb
Colorblindness is an X-linked recessive trait. The shaded figures in the pedigree represent individuals who are colorblind. (B) represents the allele for normal color vision, and (b) represents the allele for colorblindness. What would Sue’s genotype be?

51. XBXb
Colorblindness is an X-linked recessive trait. The shaded figures in the pedigree represent individuals who are colorblind. (B) represents the allele for normal color vision, and (b) represents the allele for colorblindness. What would Sara’s genotype be?

52. XBXb
Colorblindness is an X-linked recessive trait. The shaded figures in the pedigree represent individuals who are colorblind. (B) represents the allele for normal color vision, and (b) represents the allele for colorblindness. What would Jen’s genotype be?

53. What is the most probable genotype for the first set of parents?
Rr x rr
In a species of birds, red beak color (R) is dominant to white beak color (r).
Parents # gray # white
1. Red x white
2. Red x Red
3. white x white
4. Red x white
What is the most probable genotype for the first set of parents?

54. What is the most probable genotype for the third set of parents?
rr x rr
In a species of birds, red beak color (R) is dominant to white beak color (r).
Parents # gray # white
1. Red x white
2. Red x Red
3. white x white
4. Red x white
What is the most probable genotype for the third set of parents?

55. Codominance
In humans, A and B blood types are equally expressed in individuals with type AB blood. This is an example of what type of dominance?

56. Explain genetic linkage.
The chromosomes above represent two possible outcomes of a crossing over event during meiosis. When genes are located on the same chromosome the tendency to sort together is based on how far apart they are from one another.
Scenario 1 shows what might happen if alleles are located close together – the genes stay together during gamete formation. Scenario 2 shows what might happen if alleles are located far apart – the genes can form new combinations due to a higher chance of crossing over.
Explain genetic linkage.

57. Dad = IAi, Mom = IBi.
A dad with type A blood and a mother with type B blood have a child with type O blood. What are the genotypes of the parents?

58. Dad = IAIA, Mom = IBIB.
A dad with type A blood and a mother with type B blood have a child with type AB blood. What are the genotypes of the parents?

59. Dad = ii, Mom = IBi.
A dad with type O blood and a mother with type B blood have a child with type O blood. What are the genotypes of the parents?