Name___________________________________ Class ______________________ Date _______
Reading Guide

Section 11–3 Other Patterns of Inheritance (pages 319–322)

Beyond Dominant and Recessive Alleles

For Questions 1-7, write True if the statement is true. If the statement is false, change the underlined word to make the statement true.

                                  1. When offspring show a blend of the parents’ traits, one allele is dominant over the other.

                                  2. In complete dominance, the heterozygous phenotype lies somewhere between the two homozygous phenotypes.

                                  3. A heterozygous individual that exhibits the traits of both parents is an example of codominance.

                                  4. Many genes exist in several forms and are said to have codominant alleles.

                                 5. While multiple alleles may exist in a population, an individual usually carries only two alleles for each gene.

                                 6.  Traits produced by two or more genes are codominant.                                                                                                                                                                                                        

                                 7.  Polygenic traits often show a wide range of phenotypes.

 

8.      A plant breeder produced a purple flower by crossing a red parent with a blue parent. Use RR as the genotype for the red parent and BB for the blue parent. Complete the Punnett square to show the resulting genotypes and phenotypes of the offspring.

 

 

Gamete allele:                         

Gamete allele:                          

Gamete allele:      

Genotype:                  

Phenotype:                 

Genotype:                    

Phenotype:                  

Gamete allele:      

Genotype:                  

Phenotype:                 

Genotype:                    

Phenotype:                  

 

For Questions 9-11, refer to the Punnett square above.

9.      What type of inheritance is the example in Question 8?

 

10.  If the offspring had been red and blue spotted flowers, what kind of inheritance would be most likely?

 

11.  Explain the difference between multiple alleles and polygenic traits.

 

Genes and the Environment

12.           Some                          produce variable traits depending on environmental conditions.

13.    Western white butterflies vary in their wing color because their                              varies depending on when they hatch.

14.                                is an environmental variable that affects wing color in western white butterflies.

For each of the following examples, write G if the trait is determined by genotype, and E if it is determined by environment.

15.                               Turtles whose eggs hatch at higher temperatures tend to be female.

16.                                A blue-eyed girl is born to two blue-eyed parents.

17.                               Bees in a colony are assigned different jobs. As they develop, workers begin to look dramatically different.

18.                                A pair of twins is separated at birth. They grow up in different countries and speak different languages.

19.                                A litter of puppies is born. They are all gray except one, which is brown.

20.                                Tall pea plant seeds are planted in different locations around a yard. They produce plants of different heights.

21.                                A kitten is born with six toes.

22.                                A rabbit is born weak with hunger.

Section 14–1 Human Chromosomes (pages 392-397)

Karyotypes

23.  What is a karyotype?

 

 

24.  From what is a karyotype made?

 

 

25.  What is an autosome?

 

______   26.  How many chromosomes are in a normal human karyotype?

A.  23                                         C.  44

B.  46                                          D.  2 (either XX or XY)

               27.  Which of the following genetic abbreviations denotes a male human?

                     A.  23, XX                                   C.  46, XX

                     B.  23, XY                                  D.  46, XY

               28.  Why is the ratio of male to female births roughly 50:50?

                     A.  All egg cells carry an X chromosome.

                     B.  Half of all egg cells carry a Y chromosome.

                     C.  All sperm cells carry an X chromosome.

                     D.  Half of all sperm cells carry a Y chromosome.

               29.  How are the X and Y chromosomes different?

                     A.  Only one is an autosome.     C.  The Y carries fewer genes than the X.

                     B.  The X is smaller than the Y. D.  Only females have a Y.

                 30.  All human cells carry

                     A.  at least one X chromosome. C.  a pair of X chromosomes.

                     B.  at least one Y chromosome. D.  one X and one Y chromosome.

have a single X chromosome. However, half of all sperm cells carry an X

Transmission of Human Traits

 

31. Colorblindness is a sex-linked trait. Let B represent an allele for normal color vision. Let b represent an allele for colorblindness. The genotype for a male with normal color vision is XBY. The genotype for a female heterozygous for normal color vision is XBXb. Complete the Punnett square to show the genotypes of their possible offspring.

Parent Genotype ____________________ X Parent Genotype: _________________

 

XB

Y

 

XB

 

 

 

 

 

Xb

 

 

 

 

 

 

32. Use your Punnett square to explain why a female with one b allele has normal color vision but a male with one b allele is colorblind.

 

33. How does the cell “adjust” to the extra X chromosome in female cells?

 

34. What is a Barr body?

 

35. Why don’t males have Barr bodies?

      

36. Is a cat with three colors of spots more likely to be male or female?

      

Human Pedigrees           

37. What does a pedigree chart show? It

 

 

 

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.

 

 

 

 

 

_____38. A person that expresses the trait                  _____41. Represents a marriage

_____39. A male                                                         _____42. A female

_____40. A person who does not express the trait      _____43. Connects parents to their children

eople who are heterozygous are generally healthy and are resistant on the nature

Section 14–2 Human Genetic Disorders black spots is switched off.

Chromosomal Disorders

44. What occurs during nondisjunction? H

 

 

45. Is the following sentence true or false? If nondisjunction occurs, gametes may have

abnormal numbers of chromosomes. ______

 

46. The condition in which an individual has three copies of a chromosome is known as ___________________________________, which means “three bodies.”

 

47. Is the following sentence true or false? Down syndrome occurs when an individual has

two copies of chromosome 21. ______

 

48. What is the genotype and phenotype of a person with Turner’s syndrome?

 

DNA fingerprint

49. What happens when a male has XXY sex chromosomes?