1. genetics STAAR review

2. Incomplete/codominance video
Genetics video
Incomplete/codominance video
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Monohybrid tutorial:
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Dihybrid tutorial:
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Sex linked video:
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3. Gregor Mendel worked with pea plants to learn the basic patterns of inheritance.
Phenotype – what the organism looks like
Genotype – the gene (letter) combination – either Homozygous (TT or tt) or Heterozygous (Tt)
Homozygous (aka: pure breeding, true breeding)
Homozygous dominant- HH (shows dominant trait)
Homozygous recessive- hh (shows recessive trait)
Heterozygous (aka: hybrid)- Ht (shows dominant trait)
Monohybrid Cross – follows 1 trait through several generations
Dihybrid cross – follows two traits
Simple Genetics

4. Simple Genetics- monohybrid cross
P(parental) TT x tt F1 generation
T T T t
t geno- all Tt T geno – ¼ TT, ½ Tt, ¼ tt (1:2:1 geno. ratio)
t pheno – all tall t pheno – ¾ Tall; ¼ short (3:1 pheno. ratio)
F2 generation
T t T t
T geno- ½ TT; ½ Tt (1:1 geno. ratio) t geno – ½ Tt; ½ tt (1:1 geno. ratio)
T pheno – all Tall t pheno– ½ Tall; ½ short (1:1) Tt TT Tt tt TT Tt Tt tt
Simple Genetics- monohybrid cross

5. Dihybrid Cross BbEe x BbEe B- brown b- white E- short ears
e- long ears
9 brown and short ears
3 brown and long ears
3 white and short ears
1 white and long ears
Dihybrid Cross

6. Complex Genetics Incomplete Dominance – blended/mixed phenotype
Ex) snap dragons  Red (RR) X White (R’R’)  all Pink
R R R R’
R’ geno- all RR’ R’ geno- ¼ RR; ½ RR’; ¼ R’R’
R’ pheno-all pink R’ pheno- ¼red; ½ pink; ¼ white
Codominance – both parental phenotypes show up in offspring
Ex) Chickens  Black x White Black and White feathers
Multiple Allelism – trait with 3+ alleles
ex) A, B, O blood types
Complex Genetics
RR’ RR
RR’
R’R’

7. Complex Genetics Sex Linked – genes carried on sex chromosomes
Ex) hemophilia, color blindness
Cross shows a carrier female and a normal male. For a female to inherit the trait the father must have it and the moth must at least be a carrier
Karyotypes – show if it is a boy or girl and if there is too many or too few chromosomes
Ex) Down’s Syndrome (aka Trisomy 21)
Complex Genetics

8. Vocab review game

9. Term: genotype Term: sex-linked Definition: genetic make- up; letters
Ex. AA, Aa, aa
Definition: traits controlled by the X chromosome
XRXr
XrY

10. Term: Heterozygous Term: dominant
Definition: hybrid; two different alleles for a trait
Ex. Aa
Definition: trait that is observed; masks/hides the recessive
Ex. A

11. Term: homozygous Term: nondisjunction
Definition: pure; two of the same alleles for a trait
Ex. AA or aa
Definition: when chromosome pairs fail to separate during Meiosis

12. Term: incomplete dominance Term: karyotype
Definition: neither allele is dominant; hybrid is a blend of the alleles
Ex. red x white = pink
Definition: picture of paired chromosomes
Definition: picture of paired chromosomes

13. Term: recessive Term: phenotype Definition: trait that is masked
Definition: physical appearance based on alleles

14. Term: codominant Term: blood type
Definition: both alleles are dominant; hybrid shows both alleles
Ex. roan cow
Definition: trait you get with a combination of these alleles- IA, IB,i

15. What am I game

16. Incomplete dominance Gregor Mendel Inheritance when
blue X yellow = green
Who discovered how some things are inherited

17. genotype heterozygous Homozygous dominant hybrid Homozygous recessive

18. phenotype
genotype
When you look and see a watermelon has stripes BB

19. Practice eoc questions

20. Purple flowers are dominant over white flowers
Purple flowers are dominant over white flowers. A pure purple flowered plant is crossed with a homozygous recessive plant.
What percent of the offspring are homozygous?
A. 0%
B. 25%
C. 50%
D. 100% A

21. If red snapdragon flowers are crossed with white snapdragons, pink snapdragon flowers are produced.
If two pink snapdragons are crossed what are the expected phenotypic results?
A. ¼ red, ½ pink, ¼ white
B. ¾ red, ¼ white
C. ¼ red, ¾ white
D. ½ red, ½ white A

22. A boy with blood type A has a sister with blood type B
A boy with blood type A has a sister with blood type B. What are the possible blood types of their parents?
Type O and type O
Type AB and type O
Type AA and type B
Type A and type A B

23. A. Chromosomes of different lengths B. Two X chromosomes
When viewing a karyotype to detect genetic disorders, which of the following would be a concern?
A. Chromosomes of different lengths
B. Two X chromosomes
C. Twenty-three pairs of chromosomes
D. Three chromosomes in any one set D

24. Eye color in fruit flies is a sex linked trait, where red is dominant
Eye color in fruit flies is a sex linked trait, where red is dominant. If a female fruit fly is a carrier and is mated with a white-eyed male, what percent of their offspring would have white eyes?
A. 0% B. 25% C. 50% D. 75% C

25. When roan cattle are mated, 25% of the offspring are red, 50% are roan, and 25% are white. Upon examination, it can be seen that the coat of a roan cow consists of both red and white hairs. What controls this trait?
A. Incomplete dominance
B. Codominant alleles
C. Sex-linked genes
D. Polygenic inheritance B

26. A man heterozygous for blood type A marries a woman heterozygous for blood type B. What is the chance that their first child will have type O blood?
A. 0%
B. 25%
C. 50%
D. 75% B

27. A. Nondisjunction; down syndrome
  When homologous chromosomes fail to separate during meiosis, which is known as _____________. This event can lead to a disorder such as ___________. A
A. Nondisjunction; down syndrome
B. Translocation; diabetes
C. Disjunction; Cystic fibrosis
D. Crossing over; sickle cell anemia

28. If a mother develops melanoma, skin cancer, why is she not concerned that her unborn child will have the same condition?
A. The mutation has not occurred in the gametes and therefore is not inheritable
B. The mutation has not occurred in the somatic cell and therefore is not inheritable
C. The DNA of the child only came from the father
D. The DNA of the child can be repaired through gene therapy A

29. Chromosomal Abnormality Pedigree Blood Type
Vocabulary
Genotype
Phenotype
Allele
Dominant
Recessive
Incomplete Dominance
Codominance
Multiple Alleles
Sex – linked traits
Homozygous
Heterozygous
Sex chromosomes
Karyotype
Chromosomal Abnormality
Pedigree
Blood Type
Trisomy 21 (Down’s Syndrome)
Essential Questions
Distinguish when recessive traits are expressed in the phenotype.
What are examples of human sex-linked traits?
Who is affected most often?
Interpret pedigrees and karyotypes in order to identify patterns of inheritance?
Generalize autosomal inheritance patterns.
Explain the connections between genetics and the environment with regards to general traits as well as human genetic disorders.

30. Red and blue are 2 popular variations of a particular flower
Red and blue are 2 popular variations of a particular flower. A gardener began experiments breeding with this flower. His results are shown in the following 2 ratios:
F1: 0 red, 0 blue, 100 purple
F2 25% red, 25% blue, 50% purple
What type of inheritance is shown by these flowers?
In mice, brown hair is dominant to white. Cross a heterozygous female with a heterozygous male. The phenotypic ratio will yield?
A unit of heredity, composed of a segment of DNA on a chromosome that contains information required to manufacture a protein and will eventually be expressed as a trait, is called a:

31. genetics game:
genetics hangman:
human genetics matching:
Mendel’s laws game: