Question

name joshua wray class date human traits 5. what does a pedigree chart show? match the labels to the parts of the pedigree chart shown below. some of the parts of the pedigree chart may be used more than once. pedigree chart 6. a person that expresses the trait 9. represents a marriage 7. a male 10. a female 8. a person who does not express the trait 11. connects parents to their children 12. give two reasons why it is impossible to associate some of the most obvious human traits with single genes. a. b. human genes 13. why is it difficult to study the genetics of humans? 14. circle the letter of each sentence that is true about human blood group genes. a. the rh blood group is determined by a single gene. b. the negative allele (rh-) is the dominant allele. c. all of the alleles for the abo blood group gene are codominant. d. individuals with type o blood are homozygous for the i allele (ii) and produce no antigen on the surface of red blood cells.

Explanation:

• Question 5: A pedigree chart shows the inheritance pattern of a trait within a family over generations. It visually represents family relationships (parents - children, marriages) and which family members express a particular trait.
• Question 6: In a pedigree, a filled - in symbol (either circle for female or square for male) represents a person that expresses the trait.
• Question 7: A square is used to represent a male in a pedigree chart.
• Question 8: An unfilled symbol (circle or square) represents a person who does not express the trait.
• Question 9: A horizontal line connecting a circle (female) and a square (male) represents a marriage.
• Question 10: A circle is used to represent a female in a pedigree chart.
• Question 11: A vertical line connecting parents (connected by a marriage line) to their children represents the parent - child relationship.
• Question 12:
• a. Many human traits are polygenic (controlled by multiple genes). For example, height is influenced by several genes.
• b. Environmental factors also play a role in trait expression. For instance, diet can affect the expression of traits related to body weight.
• Question 13: Humans have a long generation time (about 20 - 30 years between generations), which makes it difficult to observe multiple generations in a short time. Also, controlled breeding (like in plant or animal genetics studies) is unethical in humans.
• Question 14:
• a. The Rh blood group is determined by a single gene (the RHD gene). So, this statement is true.
• b. The positive allele (\(Rh^{+}\)) is dominant over the negative allele (\(Rh^{-}\)). So, this statement is false.
• c. In the ABO blood group, \(I^{A}\) and \(I^{B}\) are codominant, but \(i\) (the allele for type O) is recessive. So, this statement is false.
• d. Individuals with type O blood have the genotype \(ii\) and have no A or B antigens on their red blood cells. So, this statement is true.

Answer:

• 5. The inheritance pattern of a trait within a family over generations.
• 6. Filled - in symbol.
• 7. Square.
• 8. Unfilled symbol.
• 9. Horizontal line connecting male and female.
• 10. Circle.
• 11. Vertical line from parents to children.
• 12. a. Many human traits are polygenic. b. Environmental factors influence trait expression.
• 13. Long generation time and unethical to do controlled breeding.
• 14. a. True; d. True.