sex chromosomes

Question 1

turner syndrome

Answer 1

1 in 3000 females

- Short
- Low hairline
- Broad chest
- Normal intelligence
- Likely sterile

Question 2

poly-X females

Answer 2

1 in 1000 females

- No distinctive features
- Tall and thin
- Few are sterile
- Incidence of mental retardation slightly greater

XXXX and XXXXX

- Normal female anatomy
- Retarded
- Physical problems

Question 3

klinefelter syndrome

Answer 3

• 1 in 1000 males
  
  • Small testes
  • Reduced facial and pubic hair
  • Tall
  • Sterile
  • Normal intelligence
    Majority is XXY but also XXXY, XXXXY, XXYY

Question 4

animal with XX-XO sex determination

Answer 4

grasshopper

Question 5

animal with ZZ-ZW sex determination

Answer 5

Birds, snakes, amphibiens and fish

Question 6

advantages and stats of the fruit fly

Answer 6

• Small size
  
  • Short generation time of 10 days at room temperature
  • Each female lays 400-500 eggs
  • Easy to culture in laboratory
  • Small genome
  • Large chromosomes
  • Many mutations available

Size: 2-3 mm in lenght
Anatomy: 3 body segments, 6 legs, 1 pair of wings
Habitat: feeds and reproduces on fruit

Question 7

genome and contribution of genetic of fruit fly

Answer 7

• Chromosomes: 3 pairs of autosomes and X and Y (2n=8)
  
  • Amount of DNA: 175 million base pairs
  • Number of genes: 14,000
  • % of genes in common with humans: 50%
  • Average genze size: 3000 base pairs
  • Genome sequenced in year: 2000

Contribution to genetics:

- Basic principles of heredity including sex-linked inheritance, multiple alleles, epistatsis, gene mapping…
- Mutation research
- Chromosome variation and behaviour
- Population genetics
- Genetic control of pattern information
- Behavioral genetics