1. 1.The trait being traced in this pedigree is DOMINANT. How would you know that by looking at the pedigree? 2.What is the genotype of: a. Person #1, how do you know? b. Person #2, how do you know? c. Person #3, how do you know? 1 2 3

2. Section 12.2 Summary – pages 315 - 322 Patterns of inheritance that are explained by Mendel’s experiments are often referred to as “simple”. However, many inheritance patterns are more complex than those studied by Mendel. COMPLEX PATTERNS OF INHERITANCE

3. Section 12.2 Summary – pages 315 - 322 For example: A homozygous red-flowered plant (RR) is crossed with…. a homozygous NO PIGMENT-flowered plant (R′ R′), all of the first generation offspring will have pink flowers- they are only showing half of the red pigment. INCOMPLETE DOMINANCE Only displaying half of one allele

4. Section 12.2 Summary – pages 315 - 322 In co-dominance, both alleles are expressed equally. CO-DOMINANCE An expression of both alleles

5. Section 12.3 Summary – pages 323 - 329 Co-dominance in Humans One example of this in humans is sickle-cell disease. Sickle-cell diseases cause the red blood cells to be deformed.

6. Section 12.3 Summary – pages 323 - 329 In an individual who is homozygous for the sickle-cell allele, the oxygen-carrying protein hemoglobin differs by one amino acid from normal hemoglobin. Hb SS Co-dominance in Humans Individuals who are heterozygous for the allele produce both normal and sickled hemoglobin, an example of codominance. Hb AS Individuals homozygous for the normal hemoglobin allele have this genotype : Hb AA

7. Section 12.2 Summary – pages 315 - 322 Although each trait has only two alleles in the patterns of heredity you have studied thus far, it is common for more than two alleles to control a trait in a population. Traits controlled by more than two alleles have multiple alleles. An example is Blood Type. MULTIPLE ALLELES More than two alleles in a population

8. Blood Donation You cannot receive blood from just anyone. Because of this, donating blood is extremely helpful for doctors and hospitals. Type O– blood is considered the “universal donor” because it can be donated to people of any blood type. Type AB+ blood is considered the “universal recipient” because people with this type can receive any blood type.

9. Section 12.3 Summary – pages 323 - 329 The gene for blood type, gene l, codes for a molecule that attaches to the surface of red blood cells. Different blood types have different types of molecules on the outside of their red blood cells The ABO Blood Group The l A and l B alleles each code for a different molecule. Your immune system recognizes the red blood cells as belonging to you. If cells with a different surface molecule enter your body, your immune system will attack them.

10. Section 12.2 Summary – pages 315 - 322 Polygenic inheritance is the inheritance pattern of a trait that is controlled by two or more genes. POLYGENIC INHERITANCE Controlled by many genes in an individual POLY = MANY GENIC = GENES This means there can be an ARRAY of phenotypes.

11. Section 12.2 Summary – pages 315 - 322 The result is that the phenotypes usually show a continuous range of variability from the minimum value of the trait to the maximum value. POLYGENIC INHERITANCE Along with skin color, examples of polygenic inheritance is hair color, eye color, and height.

12. Section 12.2 Summary – pages 315 - 322 In humans the diploid number of chromosomes is 46, or 23 pairs. There are 22 pairs of homologous chromosomes called autosomes. Homologous autosomes look alike. The 23 rd pair of chromosomes differs in males and females. GENDER DETERMINATION

13. Section 12.2 Summary – pages 315 - 322 These two chromosomes, which determine the gender of an individual, are called sex chromosomes and are indicated by the letters X and Y. GENDER DETERMINATION MALES XY FEMALES XX

14. Section 12.2 Summary – pages 315 - 322 Males usually have one X and one Y chromosome and produce two kinds of gametes, X and Y. Females usually have two X chromosomes and produce only X gametes. It is the male gamete that determines the sex of the offspring. GENDER DETERMINATION

15. Section 12.2 Summary – pages 315 - 322 Traits controlled by genes located on sex chromosomes are called sex-linked traits. The alleles for sex-linked traits are written as superscripts of the X or Y chromosomes. Because the X and Y chromosomes are not homologous, the Y chromosome has no corresponding allele to one on the X chromosome and no superscript is used. X Y R

16. Section 12.3 Summary – pages 323 - 329 Many human traits are determined by genes that are carried on the sex chromosomes; most of these genes are located on the X chromosome. Sex-Linked Traits in Humans If a son receives an X chromosome with a recessive allele, the recessive phenotype will be expressed because he does not inherit on the Y chromosome. X Y The female would have to have the recessive allele on both of her X chromosomes for it to be expressed X X Recessive Sex-Linked Traits: r rr

17. Section 12.3 Summary – pages 323 - 329 Sex-Linked Traits in Humans Two traits that are governed by X-linked recessive inheritance in humans are red-green color blindness and hemophilia. People who have red-green color blindness can’t differentiate these two colors. Color blindness is caused by the inheritance of a recessive allele at either of two gene sites on the X chromosome.

18. Section 12.3 Summary – pages 323 - 329 Hemophilia is an X-linked disorder that causes a problem with blood clotting. Hemophilia: An X-linked disorder About one male in every 10 000 has hemophilia, but only about one in 100 million females inherits the same disorder.

19. Section 3 Check How do red blood cells of phenotype O differ from the cells of the other phenotypes? Question 1 Answer Red blood cells of phenotype O display no surface molecules.

20. Section 2 Check What is the difference between simple Mendelian “simple” inheritance and codominant inheritance? Question 2

21. Section 2 Check If the offspring of human mating have a 50-50 chance of being either male or female, why is the ratio not exactly 1:1 in a small population? Question 3 Answer The ratio is not exactly 1:1 because the laws of probability govern fertilization.

22. Making Babies (on paper) Today you will be finding out which allele YOU will be passing on to your baby. (We will figure out your partner’s alleles next time) You will receive a penny. For each trait on you paper, you will toss the penny at your desk. If it lands on heads, write the Dominant allele in the space “Your Gamete” If it lands on tails, write the Recessive allele in the space “Your Gamete” “Your Gamete” is the only column we are doing today. If you prove that handling a penny is too much for you (ridiculous)- you will receive a detention and you will be given a very boring alt. assignment.

23. FACE SHAPELETTER “R” SKIN COLORLETTER “S” HAIR TYPELETTER “C” WIDOW’S PEAKLETTER “W” EYEBROW THICKNESS LETTER “B” EYEBROW PLACEMENT LETTER “N” EYE COLORLETTER “A” EYE SEPERATIONLETTER “E” EYE ANGLELETTER “H” EYELASHESLETTER “L” LIP THICKNESSLETTER “T” CHEEK DIMPLESLETTER “D” NOSE SIZELETTER “Q” NOSTRIL FLARE SHAPE LETTER “G” EAR LOBE ATTACHMENT LETTER “F” EAR HAIRLETTER “K” CHEEK FRECKLESLETTER “Z” FOREHEAD FRECKLES LETTER “Y” Remember: If it lands on heads, write the Dominant allele in the space “Your Gamete” If it lands on tails, write the Recessive allele in the space “Your Gamete” Chro m. # TraitYour Gamete' s Allele Donated Gamete 's Allele Baby's Genot ype Phenotype 1Face Shape r 2Skin Color S Example: 1.If you toss tails for face shape 2.If you toss heads for skin color

24. 1. Face Shape/ RR=round Rr=round rr=square10. Eyelashes/ LL=Iong Ll=long ll=short 2. Skin Color / SS=dark, Ss=tan, ss=fair11. Lip thickness/ TT=thick Tt=medium tt--thin 3. Hair Type/ CC=curly Cc=wavy cc=straight 12. Cheek Dimples/ DD=present Dd=present dd=absent 4. Widow's Peak / WW or Ww=widow's peak ww=no widow's peak 13. Nose Size / QQ=large Qq=medium qq=small 5. Eyebrow Thickness/ BB=bushy Bb=bushy bb=fine 14. Nostril Flair Shape/ GG or Gg = rounded, gg = pointed 6. Eyebrows / NN=unconnect Nn=unconnect nn=connected 15. Ear Lobe Attachment/ FF or Ff=free, ff=attached 7. Eye Color / AA=brown, Aa=green, aa= blue16. Ear Hair/ KK or Kk=no hair, kk=hairy 8. Eye Separation/ EE=wide Ee=normal ee=narrow 17. Cheek Freckles/ ZZ=present Zz=present zz=absent 9. Eye Angle/ HH or Hh=horizontal, hh=upward18. Forehead Freckles/ YY or Yy=yes, yy=no