-- synapsis: homologous chromosomes are coming close together and bivalents are formed.
-- crossing-over: non-sister chromatids of homologous chromosomes interchange genes
The pairing (formation of bivalents) allows crossing over to take place and this enables genetic variations in the gametes.
synapsis
Synapsis is the process in which the genetic material is exchanged between two homologous non sister chromatids (the pair of chromosomes which are same in shape,size but not identical) whereas chaisma is the actual site where synapsis occur.
Crossing over occurs during synapsis, prophase I.
prophase I
crossing over
Crossing over is the exchange of genetic material between chromatids. This is also known as synapsis, and it occurs during prophase one of meiosis.
synapsis
Synapsis is the process in which the genetic material is exchanged between two homologous non sister chromatids (the pair of chromosomes which are same in shape,size but not identical) whereas chaisma is the actual site where synapsis occur.
Crossing over occurs during synapsis, prophase I.
prophase I
crossing over
crossing over
the synapsis and crossing over of homologous chromosomes
Gametes produced by crossing over are called non parental and possess more genetic variations as compared to those produced with out crossing over which possess much less genetic variations.
the frequencies of crossing over between genes
homologous chromosomes exchange alleles during crossing over.
It would appear you are speaking of crossing over which takes place in Prophase I of meiosis.