library(ape)
m <- as.matrix(read.table("distance_matrix.txt", head=T, row.names=1))
arbol <- nj(as.dist(m))
arbol$edge.length <- arbol$edge.length + abs(min(arbol$edge.length))+1
pdf('FGA_tree.pdf',width=10, height=10,pointsize=0.1)
plot(arbol,cex=0.9,edge.width=1, font=15, tip.color = "blue", type="fan")
dev.off()