Gene & sex linkage

Question 1

Thomas Hunt Morgan

Answer 1

pioneered study of fruit fly - Drosophila - which have become a key model organism is genetic research

Question 2

sex chromosomes & linkage in mammals

Answer 2

• females have 2 X chromosomes
• males have X & Y
• males produce 2 kind of gametes = X or Y
• sex does not depend fully on which of these fuse w/ egg

Question 3

sex chromosomes and linkage in birds

Answer 3

• Males have 2 Z chromosome
• Females have one Z and one W

Question 4

sex chromosomes and linkage in bees

Answer 4

• males are haploid
• females are diploid

Question 5

sex chromosomes and linkage in Galapagos giant turtles

Answer 5

• sex is dependant on temperature eggs are incubated at

Question 6

hemizygous

Answer 6

a gene that is present in a single copy in an otherwise diploid individual
- males = XBY, XbY

Question 7

lyonisation

Answer 7

• early in embryo development, one of 2 X chromosomes inactivates by supercoiling down into Barr body
• this won’t be a unanimous choice between cells throughout body