Genetics Honors NOtes 2017 SHORT p2.notebook. May 26, 2017

Transcription

1 Do Now A man and woman want to predict the chances of their offspring having dimples. The woman is heterozygous for dimples and the man does not have dimples. What is the chance of having a child with dimples? ** Name the type of inheritance ** 1

2 Dihybrid Cross used to predict the possible genotype of offspring for two traits D= E= d= e= Step 1: Determine Parent Genotype Step 2: Determine Alleles Received Step 3: Complete Punnett Square Step 4: Determine Genotype and Phenotype Ratios 2

3 Do Now Two dogs have puppies! The male dog is homozygous brown fur and heterozygous floppy ears. The female dog is heterozygous for brown fur and has straight ears. B/b= fur F/f=ears List the genotype and phenotype fractions for the cross. 3

4 Do Now I have a purple flower and want to know it's genotype. I know that purple is dominant. 1. What is the genotype? 2. What can we do to be sure it's the genotype? 4

5 Test Cross When the genotype of a dominant individual is unknown, cross the individual with a homozygous recessive The outcome of the cross determine the genotype of the unknown 5

6 Pedigree 6

7 Fill in the pedigree for Achondroplasia. Use the variable A. 7

8 P: F1: F2: Self Fertilize: Cross Fertilize: True Breeding: Hybrids: 8

9 Mendel's Four Hypotheses 1. There are alternative versions of genes that account for inherited characteristics 2. For each characteristic, an organisms inherits two alleles (one from each parent) 3. If the two alleles differ, then the one that determines the organisms phenotype is called the dominant allele 4. A sperm or egg carries only one of each allele for each inherited characteristic because the alleles separate from each other during the production of gametes *** Law of segregation**** Mendel's Three Laws 1. Law of Segregation 2. Law of Independent Assortment 3. Law of Dominance 9

10 Do Now 1. Whether an allele is dominant or recessive depends on... A. how common the allele is, relative to other alleles B. whether it's inherited from the mother or father C. which chromosome it's on D. whether or not it's linked to other genes E. whether it or another allele determine phenotype 2. Edward was (Ss) heterozygous for sickle cell disorder. The alleles S and s are... A. on X and Y chromosomes B. linked C. on homologous chromosomes D. both present in Edward's sperm cells HMWK: R/O , Lab quiz on Monday (5/20) 10

11 Genetics Honors NOtes 2017 SHORT p2.notebook Multiple Alleles (blood type) Traits determined by more than 2 alleles Ex. Blood Typing (3 alleles ABO) > A and B are codominant to O Alleles: Let's try some problems! 1. Maria is type O and her sister is type AB. The girls know both their maternal grandparents were type A. What are the genotypes of her parents? 2. A man is type A and a woman is type B. What are the possible different genotypes the children could have? 3. A woman is type AB and a man is type O. Their first child is born type A+ blood and the second child is born with type A blood. What is the mother's genotype? 4. Try this cross heterozygous A with heterozygous B heterozygous +. 11

12 Do Now A man who is type AB+(heterozygous) and a woman is type O +(heterozygous) have kids. What are possible phenotypes of the children? HMWK: R/O 9.9,

13 Do Now What type blood can someone with type AB+ donate to? R/O , Lab quiz on Monday 13

14 Genetics Honors NOtes 2017 SHORT p2.notebook 14

15 Sex Linked Traits Traits located on the sex chromosomes (X or Y) SRY (sex determining region of Y) located on the Y chromosome determines male development > absence of SRY will develop ovaries X linked: gene is located on the X chromosomes Y linked: gene is located on the Y chromosome X linked recessive: > Red Green Color Blindness > Hemophilia A man who is color blind marries a woman that is heterozygous for color blindness. What is the chance of having a color blind boy? 15

16 Hemophilia Sex linked disorder characterized by delayed blood clotting Located on the X Chromosome Seen in the Royal Family of England 16

17 Environmental Influence Twin Studies 17

18 Do Now Write in the genotypes. Use R HMWK: R/O , Genetics Test Wed (5/29), Genetics Research due Friday 18

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