Module 8 - Part 2

Question 1

NDJ of the x-chromosome in XX individual

Answer 1

• resemble what you might see for an autosome
• Two copies of the x-chromosome

Question 2

NDJ of the x-chromosome in XX individual
NDJ in meiosis I

Answer 2

• (n+1) or (n-1)
• gametes w either two copies of x or no x chromo

Question 3

NDJ of the x-chromosome in XX individual
NDJ in meiosis II

Answer 3

• n, (n+1) & (n-1)
• gametes w normal haploid gametes each w 1,2 or no x chromosomes

Question 4

NDJ of the X & Y chromosome XY individuals

Answer 4

• don’t resemble what you might see for an autosome
  (ie. 1X and 1Y)

Question 5

NDJ of the X & Y chromosome XY individuals
NDJ in meiosis I

Answer 5

• (n+1) and (n-1)
• have either gametes w XY chromo or NO sex chromo

Question 6

NDJ of the X & Y chromosome XY individuals
NDJ in meiosis II

Answer 6

• gametes that’s n, n+1, & n-1
• gametes w XX, no chromo or a set of normal haploid gametes (each w 1 Y)
• gamete w YY, no chromo or a set of normal haploid gametes (each w 1 X)

Question 7

Intersex individuals

Answer 7

Show physical characteristics typically assigned to the opposite sexes, or have gonads that’re ambiguous to one or both sexes

Question 8

Sex chromosome mutation

Answer 8

loss of androgen sensitivity due to x-linked recessive mutation of the androgen receptor

Question 9

Sex chromsome aneuploidy

Answer 9

atypical # of sex chromosome
- XXY: kleinfelter’s syndrome
- XYY: jacob’s syndrome
- XO: turner’s syndrome

Question 10

Turner Syndrome - XO

Answer 10

aka. 45, x karyotype
- missing one x chromo (monosomy)
- affects 1 in 2000-5000 females
- affected individuals are infertile
- isn’t inherited

Question 11

Klinefelter’s Syndrome - XXY

Answer 11

aka. 47, XXY karyotype
- trisomy
- additional x chromo silenced (have multiple copies of PAR gene)
- most common type in humans (1 in 500-1000 males)
- affected show reduced fertility
- isn’t inherited
- severity of symptoms depends on age XXY ppl are examined

Question 12

Jacob’s Syndrome - XYY

Answer 12

aka. 47, XYY karyotype
- have an extra Y chromo (trisomy)
- most common after KS (1 in 1000 males)
- affected show reduced fertility
- isn’t inherited
- symptoms are variable

Question 13

In somatic cells
XO:
XXY:

Answer 13

XO: genes in par regions is half of normal level
XXY: genes in par regions are over expressed
- may explain morphological abnormalities

Question 14

In germ cells
XO:
XXY:

Answer 14

XO: half normal dosage for all x-linked genes
XXY: all x-linked genes are over expressed (2-3x)
- explains sterility

Question 15

The theory of the “supermale”

Answer 15

• 1960s/70s studies revealed there was a higher freq of aneuploid men in mental institutions and prisons
• thought that ppl w an extra Y chromo were at increased risk of criminal behaviour
• 1988 study “found” that men w extra x chromo were more likely to be arsonists

Question 16

2012 study - research question

Answer 16

RQ: what is the criminal patter in men 47 XXY and 47 XYY compared to the general population

Question 17

2012 study - conclusion

Answer 17

• overall risk increased; however was similar to control when adjusting for socioeconomic parameters
• the increased risk of convictions may be partly/fully explained by the poor socioeconomic conditions

Question 18

Nature

Answer 18

behavioural (& even personality) traits are determined by biological factors (ie. genetics)

Question 19

Nuture

Answer 19

behavioural traits are determined by social factors (eg. how raised)