Cephalodiscidae mitochondrial code

{{Short description|An alternative genetic code found in the mitochondrial genome of some pterobranchians}}

The Cephalodiscidae mitochondrial code (translation table 33) is a genetic code used by the mitochondrial genome of Cephalodiscidae (Pterobranchia). The Pterobranchia are one of the two groups in the Hemichordata which together with the Echinodermata and Chordata form the major clades of deuterostomes.

Code 33 is very similar to the mitochondrial code 24 for the Pterobranchia, which also belong to the Hemichordata, except that it uses UAA for tyrosine rather than as a stop codon.{{Cite journal | last6=Halanych | first6=Kenneth M. | last5=Bernt | first5=Matthias | last4=Cannon | first4=Johanna T. | last3=Tassia | first3=Michael G. | last2=Kocot | first2=Kevin M. | last1=Li | first1=Yuanning | date=2019-01-01 | title=Mitogenomics Reveals a Novel Genetic Code in Hemichordata | journal=Genome Biology and Evolution | language=en | volume=11 | issue=1 | pages=29–40 | doi=10.1093/gbe/evy254 | pmc=6319601 | pmid=30476024}}

This code shares with many other mitochondrial codes the reassignment of the UGA STOP to tryptophan, and AGG and AGA to an amino acid other than arginine. However, the assignment of AGG to lysine in pterobranchian mitogenomes is not found elsewhere in deuterostome mitochondria but it occurs in some taxa of Arthropoda.{{Cite journal|journal= BMC Evol Biol|date=May 2011|volume=11|issue=134|pages=134|title=The enigmatic mitochondrial genome of Rhabdopleura compacta (Pterobranchia) reveals insights into selection of an efficient tRNA system and supports monophyly of Ambulacraria.|vauthors=Perseke M, Hetmank J, Bernt M, Stadler PF, Schlegel M, Bernhard D |pmid=21599892|doi=10.1186/1471-2148-11-134|pmc=3121625 |doi-access=free |bibcode=2011BMCEE..11..134P }}