is variation increased by autosomal linkage- a level biology ocr a

Autosomal linkage can both increase and decrease variation, depending on the context.

1. Decrease in Variation: Autosomal linkage refers to the fact that genes located on the same chromosome are usually inherited together. This means that they do not independently assort during meiosis, which can decrease genetic variation. This is because the genes on the same chromosome will be passed on as a unit rather than independently, reducing the number of possible combinations of genes.

2. Increase in Variation: However, autosomal linkage can also increase variation through a process called crossing over. During meiosis, homologous chromosomes can exchange segments of DNA in a process called recombination or crossing over. This can create new combinations of genes that were not present in the parent, increasing genetic variation.

So, the overall effect of autosomal linkage on variation depends on the balance between these two processes. If crossing over occurs frequently, autosomal linkage can increase variation. If crossing over is rare, autosomal linkage can decrease variation.