Mechanism of Self-Sterility in a Hermaphroditic Chordate

• Published in: Science (American Association for the Advancement of Science) Vol. 320; no. 5875; pp. 548 - 550
• Main Authors: Harada, Yoshito, Takagaki, Yuhei, Sunagawa, Masahiko, Saito, Takako, Yamada, Lixy, Taniguchi, Hisaaki, Shoguchi, Eiichi, Sawada, Hitoshi
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 25.04.2008; The American Association for the Advancement of Science
• Subjects: Amino Acid Sequence; Animals; Aquatic life; Base Sequence; Biological and medical sciences; Chordata; Chromosomes; Ciona intestinalis; Ciona intestinalis - genetics; Ciona intestinalis - physiology; Classical genetics, quantitative genetics, hybrids; Disorders of Sex Development; Female; Fertility; Fertilization; Fundamental and applied biological sciences. Psychology; Gametes; Genes; Genetic loci; Genetics of eukaryotes. Biological and molecular evolution; Invertebrata; Invertebrates; Male; Marine; Molecular biology; Molecular Sequence Data; Molecules; Ova; Ovum - metabolism; Ovum - physiology; Receptors; Self fertilization; Siblings; Spermatozoa; Spermatozoa - physiology; TRPP Cation Channels - chemistry; Selfincompatibility; Ciona intestinalis; Genetics; Prochordata; Invertebrata; Sterility; Hermaphrodite; Mechanism; Urochordata
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1152488

Hermaphroditic organisms avoid inbreeding by a system of self-incompatibility (SI). A primitive chordate (ascidian) Ciona intestinalis is an example of such an organism, but the molecular mechanism underlying its SI system is not known. Here, we show that the SI system is governed by two gene loci that act cooperatively. Each locus contains a tightly linked pair of polycystin 1-related receptor (s-Themis) and fibrinogen-like ligand (v-Themis) genes, the latter of which is located in the first intron of s-Themis but transcribed in the opposite direction. These genes may encode male- and female-side self-recognition molecules. The SI system of C. intestinalis has a similar framework to that of flowering plants but utilizing different molecules.