 Therefore, the concept of " tree-based " phylogenetic networks, which was introduced by Francis and Steel, has attracted much attention of theoretical biologists in the last few years.
<fluency>  Therefore, the concept of " tree-based " phylogenetic networks, which was introduced by Francis and Steel, has attracted much attention of theoretical biologists in the last few years.
 Therefore, the concept of " tree-based phylogenetic networks, which was introduced by Francis and Steel, has attracted much attention of theoretical biologists in the last few years.