MeiosisLectureUnit3

Question 1

Meiosis

Two Unique Events (only in Meiosis)

Answer 1

1) Genetic Recombination
2) Chromosome number Reduced (to half)

(REDUCTIONAL DIVISION)
This is achieved by:
-Pairing and segregation of homologous chromosomes
-At least one recombination (crossover) per homologous chromosome pair.

Question 2

Reductional vs Equational phases

Answer 2

One round of chromosome replication precedes Meiosis I. This DNA synthesis goes from 2C —> 4C, with chromosome # staying the same as 2N.
Note: C=Haploid DNA content
N=Haploid complement of chromosomes

Two successive rounds of division follows:

• Meiosis I= REDUCTIONAL division
  
  • 4C—>2C
  • 2N—>N, chromosome # divides by 2
• Meiosis II= EQUATIONAL division
  
  • 2C—>C
  • N—>N, chromosome # stays the same