Can you explain homologous chromosome pairing in meiosis?

Question

Example: if you have three pairs of homologous chromosomes (one long pair, one medium pair, one short pair) how many different chromosomal combinations will result from meiosis?

Answer 1

Carrie,

 

Homologous pairing implies that chromosomes that are homologous in structure and sequence, they would form a pair. Humans have 22 pairs of autosomes and a pair sex chromosomes: XX in females and XY in males. Chromosome 1 will always pair with chromosome 1,  chromosome 21 with 21 and so forth. If chromosome 1 pairs accidentally with chromosome 2 then such pairing would be unstable leading to abnormal cell division or inhibition of cell division.  Only exceptions are X and Y, they are not homologous yet they pair based on adequate sequence similarity.

 

Hope this helps.