Maximum likelihood (ML) tree of Alx proteins.

The tree was constructed using conserved amino acid sequences. The numbers on the nodes indicate the bootstrap values (1,000 pseudoreplicates). Values greater than 50% are shown. Ak: Amphipholis kochii (brittle star); Ap: Asterina pectinifera (starfish); Bf: Branchiostoma floridae (amphioxus); Dr: Dario rerio (zebrafish); Hl: Holothuria leucospilota (sea cucumber); Hp: Hemicentrotus pulcherrimus (sea urchin); Hs Homo sapiens (Human); Mr: Metacrinus rotundus (sea lily); Pm: Patiria (Asterina) miniata (starfish); Sk: Saccoglossus kowalevskii (acorn worm); Sp: Strongylocentrotus purpuratus (sea urchin).

本系统发育树基于保守氨基酸序列构建。节点处的数值为自举支持值（bootstrap value），基于1000次伪重复抽样计算，仅展示大于50%的自举值。各缩写对应的物种信息如下：Ak：科希蛇尾（Amphipholis kochii，俗称蛇尾）；Ap：细角海燕（Asterina pectinifera，俗称海星）；Bf：佛罗里达文昌鱼（Branchiostoma floridae）；Dr：Dario rerio（俗称斑马鱼）；Hl：白斑海参（Holothuria leucospilota，俗称海参）；Hp：马粪海胆（Hemicentrotus pulcherrimus，俗称海胆）；Hs：智人（Homo sapiens，俗称人类）；Mr：圆顶海百合（Metacrinus rotundus，俗称海百合）；Pm：加州海星（Patiria (Asterina) miniata，俗称海星）；Sk：柯氏囊舌虫（Saccoglossus kowalevskii，俗称橡子虫）；Sp：紫球海胆（Strongylocentrotus purpuratus，俗称海胆）。