Download The Origins of Genetic Variation (pages 135

The Origins of Genetic Variation (pages 135-136)
What does Figure 8.18 show?
Independent
Assortment of
Chromosomes
Draw how the 2
tetrads align in
example 1I.
Random
Fertilization
Explain how random
fertilization can add a huge
amount of variability to the
offspring of sexual reproduction.
Crossing Over
Crossing over is
How do the 2 tetrads align
during metaphase I in example
1?
What chromosomes will the
gametes have at the end of
meiosis I?
When does crossing over occur?
Explain how crossing over
contributes to genetic variation?
Draw how the 2
tetrads align in
example 2.
How do the 2 tetrads align
during metaphase I in example
2?
What is genetic recombination?
What chromosomes will the
gametes have at the end of
meiosis I?
When Meiosis Goes Awry (pages 137-139)
What is nondisjunction?
Nondisjunction
How can the total number of
chromosome combinations be
calculated?
When does nondisjunction
occur?
How many possible
combinations are there in
humans?
What is the result of
nondisjunction?
What does this number mean?
Trisomy 21
Describe an organism that is a
result of a gamete produced by
nondisjunction and a normal
gamete.
XYY
Describe a man that is XYY.
What might be the cause of
nondisjunction in eggs?
Turner’s
syndrome
Describe the sex chromosomes
of a woman with Turner’s
Syndrome.
What does a karyotype of
trisomy 21 show?
What are some symptoms
associated with Down’s
syndrome (name at least 4)?
Abnormal
Numbers of Sex
Chromosomes
Why do unusual numbers of sex
chromosomes upset the genetic
balance less?
1.
2.
Klinefelter’s
Syndrome
Describe the sex chromosomes
of a man with Klinefelter’s
Syndrome.
What are the characteristics of
Klinefelter’s syndrome?
What are the characteristics of
Turner’s syndrome?
Crucial role of the
Y chromsoome
How is the Y chromosome
crucial in determining a
person’s sex?