10.1 Meiosis

Question 1

Define interkinesis

Answer 1

An optional rest period between meiosis I and meiosis II, no DNA replication occurs in this stage

Question 2

Outline the formation of chiasma

Answer 2

• During synapsis in Prophase I, homologous chromosomes form tetrads
  
  • Portions of non-sister chromatids overlap, break at chiasmata, reattach to new non-sister chromatid in a system of reciprocal exchange
    
    • New combinations known as recombinants

Question 3

Explain how genetic variety is produced through independent assortment

Answer 3

• Variety produced by recombination of maternal and paternal chromosomes
  
  • For each pair of homologous chromosomes, maternal and paternal chromosomes assort to daughter cells randomly

Question 4

Explain how genetic variety is produced through crossing over

Answer 4

• Variety produced by recombination within individual chromosomes
  
  • During synapsis in Prophase I, homologous chromosomes form tetrads
  • Portions of non-sister chromatids overlap, break at chiasmata, reattach to new chromatid in a system of reciprocal exchange
  • New combinations known as recombinants

Question 5

State Mendel’s law of independent assortment

Answer 5

“Two or more pairs of alleles assort independently of one another during gamete formation”
• This law states that allele pairs separate independently during the formation of gametes
• Therefore, traits are transmitted to offspring independently of one another

Question 6

Explain the relationship between Mendel’s law of independent assortment and meiosis

Answer 6

• Mendel’s law of independent assortment applies only to traits carried on different chromosomes (unlinked genes)
  
  • Independent assortment occurs as a result of the alignment of homologs during Metaphase I, determining which maternal and paternal chromosomes assort to each daughter cell
    
    • Each pair of alleles separates independently of every other pair of unlinked alleles