default G root() {
		return gene();
	}
Return the root gene of this chromosome. Since the gene type is also a
{@link io.jenetics.ext.util.Tree}, you are able to assign it to one.
{@snippet lang="java":
final Tree<A, ?> t1 = root();
final Tree<?, ?> t2 = root();
}
This method is also an alias for {@link #gene()}, which returns the
first gene of the chromosome.

@see #gene()

@return the root tree gene of this chromosome
jenetics.ext/src/main/java/io/jenetics/ext/TreeChromosome.java