Question

Why is meiosis a source of genetic variability for organisms?

Answer 1

In meiosis the chromosomes and genes are shuffled providing multiple possible combinations of DNA.

Explanation:

In the human genome there are 23 pairs of chromosomes. In Meiosis these 46 are double and the chromosomes are arranged into four sex cells, each with only 23 chromosomes. As the chromosomes are rearranged are individually sorted this gives a huge number of possible offspring from two parents.

23 factorial = `2.59 xx 10^22` possible sex cells from one parent. which be combined with the equal number of sex cells from the other parent.

Also the chromosomes often experience crossing over where parts of one chromosome get exchanged with parts of another chromosome mixing the genes.

It is estimated that the human genome has between 20,000 and 30,000 operational genes. These genes can be arranged in what may seem as an endless number of possible combinations.

Each of these possible combinations is a source of variability. Nothing new is actually created but new or novel combinations will result in new varieties of life.