TiKz tree, i need to force move a node down

Question

I'm making this tikz figure

But i want to move the [ A C C T] box down on the same levvel as the other 3.. That is making the path line longer to the right and longer down. Please help.

Code:

\scalebox{0.7}{
\begin{tikzpicture}[
-, >=stealth',shorten >=1pt,auto,node distance=0cm,
  thick,main node/.style={rectangle,fill=blue!20,draw,text width=3cm,
        text centered,font=\sffamily\Large\bfseries},second node/.style={circle,fill=red!20,scale=0.4,draw,font=\sffamily\Huge\bfseries}, % Gates and symbols style
    and/.style={and gate US,thick,draw,fill=red!60,rotate=90,
        anchor=east,xshift=-1mm},
    or/.style={or gate US,thick,draw,fill=blue!60,rotate=90,
        anchor=east,xshift=-1mm},
    be/.style={circle,thick,draw,fill=green!60,anchor=north,
        minimum width=0.7cm},
    tr/.style={buffer gate US,thick,draw,fill=purple!60,rotate=90,
        anchor=east,minimum width=0.8cm},
% Label style
    label distance=3mm,
    every label/.style={blue},
% Event style
    event/.style={rectangle,thick,draw,fill=yellow!20,text width=2cm,
        text centered,font=\sffamily,anchor=north},
% Children and edges style
    edge from parent/.style={very thick,draw=black!70},
    edge from parent path={(\tikzparentnode.south) -- ++(0,-1.05cm)
            -| (\tikzchildnode.north)},
    level 1/.style={sibling distance=5cm,level distance=2 cm,
            growth parent anchor=south,nodes=event},
    level 2/.style={sibling distance=7cm},
    level 3/.style={sibling distance=6cm},
    level 4/.style={sibling distance=3cm} ]

  \tikzstyle{line} = [draw, -]
 \node (1) [main node]  {A C G T}
 child{  node (m) [second node] {$\bold{M}_1$}
        child{ node (2) [main node]{T G G T}}
         child{node (3) [main node]  { T G G T}}
        child{ node (4) [main node]  {T C C T}}}
         child{node (5) [main node]  { A C C T}};
\end{tikzpicture}
}

Answer 1

Using your current approach, you can use the already positioned nodes (by giving them names) to place the "ACCT" node where you need it; below I used the M_1 and "TCCT" to achieve the desired positioning:

The code:

\documentclass[border=3pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{trees,positioning,arrows}

\begin{document}

\scalebox{0.7}{%
\begin{tikzpicture}[
-, >=stealth',shorten >=1pt,auto,node distance=0cm,
  thick,main node/.style={rectangle,fill=blue!20,draw,text width=3cm,
        text centered,font=\sffamily\Large\bfseries},second node/.style={circle,fill=red!20,scale=0.4,draw,font=\sffamily\Huge\bfseries}, % Gates and symbols style
    and/.style={and gate US,thick,draw,fill=red!60,rotate=90,
        anchor=east,xshift=-1mm},
    or/.style={or gate US,thick,draw,fill=blue!60,rotate=90,
        anchor=east,xshift=-1mm},
    be/.style={circle,thick,draw,fill=green!60,anchor=north,
        minimum width=0.7cm},
    tr/.style={buffer gate US,thick,draw,fill=purple!60,rotate=90,
        anchor=east,minimum width=0.8cm},
% Label style
    label distance=3mm,
    every label/.style={blue},
% Event style
    event/.style={rectangle,thick,draw,fill=yellow!20,text width=2cm,
        text centered,font=\sffamily,anchor=north},
% Children and edges style
    edge from parent/.style={very thick,draw=black!70},
    edge from parent path={(\tikzparentnode.south) -- ++(0,-1.05cm)
            -| (\tikzchildnode.north)},
    level 1/.style={sibling distance=9cm,
            growth parent anchor=south,nodes=event},
    level 2/.style={sibling distance=4cm},
    level 3/.style={sibling distance=6cm},
    level 4/.style={sibling distance=3cm} ]

  \tikzstyle{line} = [draw, -]
 \node (1) [main node]  {A C G T}
 child{  node (m) [second node] {$\mathrm{M}_1$}
        child{ node (2) [main node]{T G G T}}
         child{node (3) [main node]  { T G G T}}
        child{ node (4) [main node]  (tctt) {T C C T}}}
         child{node (5) [main node,xshift=9cm,anchor=center]  at (m|-tctt) { A C C T}};
\end{tikzpicture}%
}

\end{document}

Answer 2

If you are open to using a specialised tree-drawing package, this is easier and you can specify your trees with a more succinct syntax.

forest is one especially powerful option:

\documentclass[tikz,border=10pt]{standalone}
\usepackage{forest}
\begin{document}
\tikzset{
  main node/.style={fill=blue!20, draw, text width=3cm, text centered, font=\sffamily\Large\bfseries},
  second node/.style={circle, fill=red!20, scale=0.4, draw, font=\sffamily\Huge\bfseries, inner sep=-2.5pt}, % Gates and symbols style
}
\begin{forest}
  for tree={
    edge path={
      \noexpand\path [\forestoption{edge}] (!u.parent anchor) -- +(0,-20pt) -| (.child anchor)\forestoption{edge label};
    },
    edge={thick},
    main node,
    l sep+=5pt,
  },
  where n children=0{tier=terminal}{},
  [A C G T
    [$\mathrm{M}_1$, second node
      [T G G T
      ]
      [T G G T
      ]
      [T C C T]
    ]
    [A C C T
    ]
  ]
\end{forest}    
\end{document}

For an explanation of how to convert a tree to the bracket notation and a basic introduction to forest, see my answer to an earlier question about drawing simple trees.