Two copies of each autosomal gene affect phenotype (physical) .

1. 7.1 Chromosomes and Phenotype Two copies of each autosomal gene affect phenotype (physical). • Mendel studied autosomal gene traits, like hair texture. Autosome – chromosome with genes not related to sex of organism (body cells)

2. X Y Gene Linkage and Mapping Several methods help map human chromosomes. • Karyotype - a picture of all chromosomes in a cell.

3. Gene Linkage and Mapping • Karyotypes can show changes in chromosomes. • deletion of part of a chromosome or loss of a chromosome • large changes in chromosomes • extra chromosomes or duplication of part of a chromosome

4. Karyotype The arrangement of all the chromosomes found in a cell. Includes: Autosomes: chromosome pairs 1-22 Sex Chromosomes: chromosome pair 23 Female = X X Male = X Y 23rd pair Female sex chromosomes X X

5. Write down three different statements you could use to describe the difference between autosomes and sex chromosomes. Process Box

6. Amniocentesis A medical technique used to collect the chromosomes of a developing fetus. It is done by inserting a needle into the womb and gathering cells in the amniotic fluid.

7. FEMALE MALE “Autosomes” Sex Chromosomes (they determine male or female)

8. 7.1 Chromosomes and Phenotype Who determines the sex of the offspring? Father – he can provide an X or Y chromosome Egg X X X XX XX X X Body Cell X XY Y Y Sperm Body Cell 1female:1male We were all female

9. 7.1 Chromosomes and Phenotype • Genes on sex chromosomes are called sex-linked genes. • Y chromosome - male characteristics . • X chromosome - genes affects many traits. . Males can pass on X or Y Females only pass on X

10. King Henry VIII is known for being ‘angry’ with his wives and blamed them for not producing a son. Explain why King Henry VIII should have found fault with himself. Process Box

11. 7.1 Chromosomes and Phenotype • Males have an XY genotype. • All of a male’s sex-linked genes are expressed. • Males have no second copies of sex-linked genes • Y chromosome is much smaller

12. Gene Linkage and Mapping Females can carry sex-linked genetic disorders. • Males (XY) express all of their sex linked genes. • Expression of the disorder depends on which parent carries the allele and the sex of the child. X chromosome carries about 1100 genes while the Y carries about 250

13. Sex-linked disorder: Color Blindness • 1. Genetic disorder found on the sex chromosome X • Known as a “sex-linked” because its found on chromosome 23 • Normal Color Vision (N) = Dominant • Colorblindness (n) = Recessive • Can’t distinguish between colors • More boys, than girls, are color blind…..WHY?

14. Complex Patterns of Inheritance • Color blindness is a problem in which red or green look like shades of gray or other colors. • The gene is carried on the X chromosome and is a recessive trait. XC Xc XC XCXC = normal female XCXc = female, normal vision (carrier) XCY = normal vision male XcY = color blind male Y

15. Sex-linked disorder: Color Blindness XC XC Color blind Dad and Normal mother produces…. Two normal sons XC XC XC XC XC 2 “carrier” daughters (NOT color blind) Y XC Y XC Y XN Xn Normal Dad and Carrier mother produces…. XN XN XN XN Xn 1 color blind son, 1 normal son 1 “carrier” daughter, 1 normal daughter Y XN Y Xn Y What is the only way to get a color-blind daughter??

16. Sex-linked disorder: Hemophila • 1. Recessive genetic disorder found on the sex chromosome X • Disease in which blood doesn’t clot properly. • Normal Blood Clotting (N) = Dominant • Hemophila (n) = Recessive

17. Sex-linked disorder: Hemophila XH XH Affected dad and Normal Mother produces…. Two normal sons Xh XH Xh XH Xh 2 “carrier” daughters Y XH Y XH Y XH Xh Normal Father and Carrier Mother produces…. XH XH XH XH Xh 1 color blind son, 1 normal son 1 “carrier” daughter, 1 normal daughter Y XH Y Xh Y What cross will ALWAYS yield you 100% affected sons?

18. (dominant) 7.1 Chromosomes and Phenotype • Carrier – has an allele for as trait or disease that is not expressed. • Carrier does not have disease symptoms but can pass it on to offspring. Dominant allele disorders are rare. Huntington’s disease is an example of a disease caused by a dominant allele.

19. Complex Patterns of Inheritance • Some traits are neither totally dominant nor totally recessive. • Incomplete dominance - when neither gene is totally dominant to the other • - Heterozygous phenotype is intermediate between the two homozygous phenotypes • Example: White flowers and red flowers produce pink flowers

20. Incomplete Dominance X Straight Curly . There is a third color that exists in the heterozygous type. It’s a mixture between the two homozygous types. Pink

21. Incomplete Dominance Incomplete Dominance

22. Incomplete Dominance Incomplete dominance

23. Complex Patterns of Inheritance • Codominant - alleles will both be completely expressed. Example – red and white flower produce a flower with BOTH colors • Codominant alleles are neither dominant nor recessive. • The ABO blood types result from codominant alleles. • Many genes have more than two alleles.

24. Heterozygous type shows BOTH phenotypes exist TOGETHER Co-dominance

25. Co-dominance

26. Co-dominance Co-dominance

27. Sickle Cell Anemia • Disease in which the body makes sickle-shaped red blood cells. Sickle-shaped cells don’t move easily through your blood vessels. They’re stiff and sticky and tend to form clumps and get stuck in the blood vessels • . • The disorder is found on chromosome 11 and is therefore not sex-linked. • The Oxygen carrying hemoglobin can not carry oxygen as efficiently and the odd-shaped cells can easily clot and break. Fatigue, pain, and organ failure due to lack of oxygen supply are common symptoms of sickle cell anemia. • It is common in the African community Actual blood cells

28. Sickle Cell Anemia Codominance Practice • Genes for blood cells: • R = Round blood cells • R’ = Sickle Cells R’ R Genotypes for blood cells RR = normal blood RR’ = some sickle cells, some normal cells R’R’ = has sickle cell anemia R R’

29. Complete the following crosses, Report the genotypes and phenotypes of the offspring R = round blood cell R’ = sickle shape RR: Round cells RR’ = sickle cell trait R’R’: sickle cell anemia Round Blood Cells x Hybrid Mixed Cells x Hybrid ---------- x ---------- ---------- x ---------- EXPECTED RESULTS -------------------------- -------------------------- -------------------------- EXPECTED RESULTS -------------------------- -------------------------- -------------------------- R’ R R R R’ R R’ R R’ R’ R’ R’ R R’ 1 sickle cell anemia 2 mixed cells 1 normal cells 2 mixed cells 2 normal cells R R R R R R R R R’ R Round Blood Cells x Sickle Sickle Cell Anemia x Pure Round EXPECTED RESULTS -------------------------- -------------------------- -------------------------- ---------- x ---------- EXPECTED RESULTS -------------------------- -------------------------- -------------------------- ---------- x ---------- R’ R’ R’ R’ 4 mixed cells 4 mixed cells R R’ R R’ R R’ R R’ R R R R’ R R’ R R’ R R’ R R

30. 1. Blood Type • there are _________________________ 4 different blood types

31. Which blood types are compatible for transfusion?? Yes or No ? O B Yes No B A Yes A A B No AB A Yes O AB

32. CoDominance: Expected Blood Types IA IA IA i 1-AB blood 1-hetero A blood 1-hetero B blood 1-pure O blood ___________ IB IAIB IAIB IB IAIB IBi 4 type AB blood ___________ ___________ ___________ ___________ ___________ IAi i ii IB IAIB IAIB IA IB IA IB i IAi IAIA IAIB IBi IA 1-pure A blood 2-AB blood 1-pure B blood 2-hetero A blood 2-heteroB blood ___________ ___________ ___________ ___________ i IAi IBi IAIB IB IBIB IA i i i IAIA IAi IAi IAi IA IA ___________ ___________ ___________ ___________ 2-hetero A blood 2- O blood 2-hetero A blood 2- O blood IAi i ii i ii ii

33. Blood type statistics… • If there are 100 people in the room:39 will be O+7 will be O-34 will be A+6 will be A-9 will be B+2 will be B-3 will be AB+and only 1 in 200 will be AB- Note: The + and – is the presence (or absence) of a third antigen (Rh).

34. Order of dominance: brown > green > blue. Complex Patterns of Inheritance • Polygenic traits are produced by two or more genes.

35. Complex Patterns of Inheritance • Epistatic gene - can interfere with the expression of all other genes. Mice have 5 genes that control fur color. 2 genes for general color 1 for shading 1 for spots 1 epistatic gene for color that overrrules all other genes

36. Complex Patterns of Inheritance • Phenotype is a combination of genotype and environment. • The sex of sea turtles depends on both genes and the environment. Warm eggs develop into females • Height is an example of a phenotype strongly affected by the environmental factors such as early nutrition and health care.

37. Gene Linkage and Mapping • Linked genes are not inherited together every time. • Chromosomes exchange homologous genes during meiosis.

38. Gene Linkage and Mapping Linkage maps – map of location of genes on a chromosome. • The closer together two genes are, the more likely they will be inherited together. • Cross-over frequencies are related to distances between genes.

39. Gene Linkage and Mapping • Cross-over frequencies can be converted into map units. • gene A and gene B cross over 6.0 percent of the time • gene B and gene C cross over 12.5 percent of the time • gene A and gene C cross over 18.5 percent of the time

40. Gene Linkage and Mapping Pedigree - chart for tracing genes in a family. • Phenotypes are used to infer genotypes on a pedigree. • Autosomal genes show different patterns on a pedigree than sex-linked genes. Widow’s peak: W = widow’s peak w = non widow’s peak

41. Gene Linkage and Mapping • If the phenotype is more common in males, the gene is likely sex-linked. Colorblindness: M = normal vision m = colorblindness

42. Some examples of human codominant traits include: blood groups: ABO, Duffy, Kell, Kidd, MNS, Rhesus red cell enzymes: acid phosphatase, adenylate kinase serum proteins: haptoglobulins cell surface antigen: human leucocyte antigen (HLA)