Historical movement and cultivation amplified that blending. After early domestication in Asia, citrus spread through Austronesian movement and later westward trade routes into the Mediterranean, where additional selection and crossing produced familiar market groups. That is why sweet orange, grapefruit, lemon, and clementine are better understood as overlapping recombination clusters than as isolated branches. Over time, human breeding tended toward sweeter, more mandarin-rich market varieties - as can be seen in the path from pomelo to mandarin, which is largely unidirectional.
The grid lines on the visualization represent a tree structure underneath. Every region is a node. When a node splits, it creates four children. The root node covers the entire space. Leaf nodes (nodes with no children) hold the actual points.
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Англия — Премьер-лига|29-й тур
Виктория Кондратьева (Редактор отдела «Мир»)