12S rRNA12S ribosomal RNA

The 12S rRNA is the RNA of the small subunit of the mitochondrial ribosome, which decodes the mRNAs of the 13 mtDNA-encoded proteins. In vertebrates its gene lies between the tRNAs for phenylalanine and valine, and its conserved stretches are widely used as markers in phylogenetics and environmental DNA studies.

Median length

955 bp

Range 71–1,249 bp

Median GC content

47.0%

Middle half 41.7%–48.8%

Species with data

2,333

Of 2,335 genomes

Strand

+ strand

In 2,275 of 2,334 genomes

12S rRNA in the mitochondrial genome of

Human Homo sapiens

RefSeq NC_012920.1 · 16,569 bp · GC 44.4% · 12S rRNA at 648–1,601, 954 bp, + strand · Species page

12S rRNARibosomal RNA

12S ribosomal RNA

Position: 648–1,601
Length: 954 bp
Strand: +
GC content: 45.5%

12S rRNA across all species

Protein-coding13
rRNA2
tRNA22
D-loop1

Outer ring: + strand, arrows run clockwise. Inner ring: − strand.
Middle ring: GC% of each gene against the whole genome (44.4%, dashed): out is GC-richer, in is AT-richer (full height = 6 points).

GC content of 12S rRNA across classes

2,332 species, reference strand as deposited in RefSeq

Mammalsn 626 · median 41.2% · middle half 39.9%–42.3%

Birdsn 423 · median 48.5% · middle half 47.6%–49.3%

Ray-finned fishesn 894 · median 48.6% · middle half 47.7%–49.6%

Reptilesn 135 · median 42.7% · middle half 41.3%–45.2%

Sharks and raysn 87 · median 41.9% · middle half 41.2%–42.5%

Amphibiansn 47 · median 42.8% · middle half 38.3%–44.7%

Other classesn 120 · median 33.8% · middle half 29.0%–40.4%

Each dot is one species. Boxes span the middle half of the species (25th to 75th percentile) and the thick line marks the median; thin lines run from the lowest to the highest value.

Compare 12S rRNA across taxa

GC content of 12S rRNA against lifespan

One point per species, coloured by class

Hover or tap a point to see the species; select it again to open its page. Legend buttons spotlight a class.

Open in the plot

Correlation with maximum lifespan

All species, each class and each order with enough species

MeasureGC%LengthGC skewAT skew

GC content of 12S rRNA against log₁₀ maximum lifespan in 32 groups; 10 pass q < 0.05. Plot it in the explorer

Correlation of GC content of 12S rRNA with log10 maximum lifespan by group
Group	n	Pearson r	Spearman ρ	q	PIC r	Partial r
All speciesevery class	2,200	+0.07	−0.07	0.001 (significant)	+0.05	+0.29
Ray-finned fishesclass Actinopterygii	826	+0.10	−0.01	0.012 (significant)	+0.06	+0.07
Mammalsclass Mammalia	614	+0.55	+0.50	< 0.001 (significant)	+0.10	+0.51
Birdsclass Aves	405	+0.14	+0.11	0.015 (significant)	+0.02	+0.16
Reptilesclass Reptilia	126	−0.02	+0.01	0.90	−0.11	−0.06
Sharks and raysclass Chondrichthyes	82	+0.05	−0.01	1.00	−0.08	+0.03
Amphibiansclass Amphibia	44	+0.10	+0.11	1.00	+0.19	–
Bivalvesclass Bivalvia	35	−0.38	−0.37	0.50	−0.06	–
Perciformesorder	208	+0.37	+0.29	< 0.001 (significant)	+0.03	+0.38
Passeriformesorder	140	−0.10	−0.09	0.40	−0.02	+0.06
Artiodactylaorder	134	+0.35	+0.27	< 0.001 (significant)	+0.05	+0.22
Cypriniformesorder	127	−0.07	−0.14	0.63	+0.09	+0.42
Carnivoraorder	123	+0.41	+0.38	< 0.001 (significant)	+0.14	+0.45
Primatesorder	112	+0.37	+0.33	< 0.001 (significant)	+0.12	+0.12
Rodentiaorder	87	+0.50	+0.49	< 0.001 (significant)	+0.21	+0.32
Squamataorder	60	−0.08	+0.02	0.88	−0.13	+0.09
Charadriiformesorder	51	+0.41	+0.43	0.046 (significant)	+0.05	+0.34
Testudinesorder	49	+0.22	+0.26	0.60	+0.10	−0.07
Psittaciformesorder	44	−0.10	+0.17	0.73	+0.04	+0.02
Chiropteraorder	43	+0.00	−0.12	0.99	−0.03	−0.05
Clupeiformesorder	38	−0.03	−0.12	0.98	−0.49	–
Pleuronectiformesorder	35	+0.26	+0.23	0.36	−0.04	+0.01
Salmoniformesorder	35	+0.25	+0.10	0.51	+0.08	+0.21
Carcharhiniformesorder	31	+0.06	−0.02	0.88	+0.02	+0.24
Cetaceaorder	28	+0.03	+0.20	0.93	−0.07	−0.13
Anseriformesorder	25	−0.36	−0.24	0.40	−0.17	−0.23
Caudataorder	25	+0.29	+0.23	0.79	+0.25	–
Siluriformesorder	23	−0.20	−0.25	0.57	+0.05	–
Centrarchiformesorder	22	+0.30	−0.00	0.39	+0.30	–
Acipenseriformesorder	21	−0.03	−0.15	0.94	+0.19	−0.33
Rajiformesorder	21	−0.14	−0.00	0.90	−0.12	–
Scombriformesorder	21	+0.19	+0.18	0.85	+0.06	–

Length of 12S rRNA against log₁₀ maximum lifespan in 32 groups; 2 pass q < 0.05. Plot it in the explorer

Correlation of Length of 12S rRNA with log10 maximum lifespan by group
Group	n	Pearson r	Spearman ρ	q	PIC r	Partial r
All speciesevery class	2,200	+0.16	+0.23	< 0.001 (significant)	+0.01	+0.06
Ray-finned fishesclass Actinopterygii	826	+0.08	+0.07	0.052	+0.02	−0.02
Mammalsclass Mammalia	614	+0.02	+0.13	0.63	−0.00	+0.00
Birdsclass Aves	405	+0.05	−0.14	0.40	+0.01	+0.00
Reptilesclass Reptilia	126	+0.21	+0.52	0.095	+0.19	+0.23
Sharks and raysclass Chondrichthyes	82	−0.10	−0.07	1.00	+0.14	−0.14
Amphibiansclass Amphibia	44	−0.28	−0.25	1.00	−0.12	–
Bivalvesclass Bivalvia	35	−0.13	−0.18	0.85	−0.24	–
Perciformesorder	208	+0.06	+0.12	0.52	−0.00	−0.12
Passeriformesorder	140	+0.02	+0.02	0.88	−0.02	−0.03
Artiodactylaorder	134	+0.10	+0.27	0.38	−0.03	+0.06
Cypriniformesorder	127	−0.20	−0.19	0.085	−0.01	−0.01
Carnivoraorder	123	+0.35	+0.44	< 0.001 (significant)	+0.03	+0.25
Primatesorder	112	−0.03	−0.13	0.80	+0.03	+0.06
Rodentiaorder	87	+0.22	+0.48	0.12	+0.01	+0.29
Squamataorder	60	+0.03	+0.02	0.95	+0.07	+0.16
Charadriiformesorder	51	+0.05	−0.11	0.88	+0.00	−0.20
Testudinesorder	49	−0.02	+0.11	0.96	+0.05	−0.06
Psittaciformesorder	44	−0.22	−0.30	0.34	+0.20	+0.03
Chiropteraorder	43	−0.15	−0.16	0.90	−0.04	−0.17
Clupeiformesorder	38	−0.14	−0.07	0.87	−0.08	–
Pleuronectiformesorder	35	+0.16	+0.33	0.63	+0.01	−0.03
Salmoniformesorder	35	+0.27	+0.30	0.46	+0.02	+0.25
Carcharhiniformesorder	31	+0.14	+0.09	0.72	+0.01	−0.33
Cetaceaorder	28	+0.25	+0.30	0.46	+0.01	+0.18
Anseriformesorder	25	−0.16	−0.05	0.72	−0.02	−0.19
Caudataorder	25	−0.25	−0.27	0.79	+0.09	–
Siluriformesorder	23	+0.26	+0.17	0.44	+0.18	–
Centrarchiformesorder	22	+0.42	+0.54	0.23	+0.27	–
Acipenseriformesorder	21	+0.23	−0.08	0.59	+0.12	−0.01
Rajiformesorder	21	−0.15	−0.27	0.90	+0.13	–
Scombriformesorder	21	−0.13	−0.18	0.89	+0.08	–

GC skew of 12S rRNA against log₁₀ maximum lifespan in 32 groups; 9 pass q < 0.05. Plot it in the explorer

Correlation of GC skew of 12S rRNA with log10 maximum lifespan by group
Group	n	Pearson r	Spearman ρ	q	PIC r	Partial r
All speciesevery class	2,200	−0.17	−0.34	< 0.001 (significant)	−0.05	−0.31
Ray-finned fishesclass Actinopterygii	826	−0.21	−0.23	< 0.001 (significant)	−0.08	−0.16
Mammalsclass Mammalia	614	−0.42	−0.37	< 0.001 (significant)	−0.05	−0.32
Birdsclass Aves	405	−0.32	−0.36	< 0.001 (significant)	−0.02	−0.13
Reptilesclass Reptilia	126	+0.15	+0.15	0.27	+0.02	−0.01
Sharks and raysclass Chondrichthyes	82	−0.01	−0.09	1.00	−0.06	+0.16
Amphibiansclass Amphibia	44	−0.12	−0.10	1.00	−0.06	–
Bivalvesclass Bivalvia	35	+0.14	+0.19	0.84	−0.03	–
Perciformesorder	208	−0.33	−0.41	< 0.001 (significant)	−0.01	−0.47
Passeriformesorder	140	+0.03	+0.06	0.85	−0.04	−0.10
Artiodactylaorder	134	−0.05	+0.11	0.70	−0.03	−0.02
Cypriniformesorder	127	−0.05	−0.01	0.73	+0.02	+0.44
Carnivoraorder	123	−0.07	−0.11	0.58	+0.15	−0.14
Primatesorder	112	−0.32	−0.35	0.001 (significant)	−0.08	−0.19
Rodentiaorder	87	−0.27	−0.28	0.047 (significant)	+0.02	−0.13
Squamataorder	60	−0.03	−0.02	0.92	+0.22	−0.09
Charadriiformesorder	51	+0.05	+0.10	0.88	+0.00	+0.01
Testudinesorder	49	−0.24	−0.21	0.60	−0.14	−0.04
Psittaciformesorder	44	+0.55	+0.60	0.008 (significant)	+0.37	+0.37
Chiropteraorder	43	+0.19	+0.15	0.90	+0.08	+0.20
Clupeiformesorder	38	−0.30	−0.18	0.50	−0.09	–
Pleuronectiformesorder	35	+0.06	−0.14	0.85	+0.09	−0.54
Salmoniformesorder	35	+0.21	+0.30	0.60	+0.34	+0.54
Carcharhiniformesorder	31	−0.21	−0.17	0.61	+0.02	+0.41
Cetaceaorder	28	−0.04	−0.31	0.90	−0.01	+0.25
Anseriformesorder	25	+0.24	+0.33	0.58	+0.13	+0.27
Caudataorder	25	−0.25	−0.14	0.79	+0.20	–
Siluriformesorder	23	−0.26	−0.22	0.44	−0.02	–
Centrarchiformesorder	22	−0.56	−0.47	0.18	−0.23	–
Acipenseriformesorder	21	−0.65	−0.19	0.013 (significant)	−0.71	−0.39
Rajiformesorder	21	+0.13	−0.11	0.90	−0.19	–
Scombriformesorder	21	−0.21	−0.05	0.85	−0.09	–

AT skew of 12S rRNA against log₁₀ maximum lifespan in 32 groups; 5 pass q < 0.05. Plot it in the explorer

Correlation of AT skew of 12S rRNA with log10 maximum lifespan by group
Group	n	Pearson r	Spearman ρ	q	PIC r	Partial r
All speciesevery class	2,200	+0.30	+0.31	< 0.001 (significant)	+0.07	+0.21
Ray-finned fishesclass Actinopterygii	826	+0.07	+0.06	0.060	+0.09	+0.19
Mammalsclass Mammalia	614	+0.33	+0.26	< 0.001 (significant)	+0.04	+0.10
Birdsclass Aves	405	+0.30	+0.33	< 0.001 (significant)	−0.10	+0.15
Reptilesclass Reptilia	126	−0.06	−0.11	0.70	+0.01	−0.10
Sharks and raysclass Chondrichthyes	82	+0.12	+0.17	1.00	+0.14	−0.04
Amphibiansclass Amphibia	44	+0.02	+0.04	1.00	+0.14	–
Bivalvesclass Bivalvia	35	−0.03	−0.09	0.97	+0.05	–
Perciformesorder	208	+0.02	−0.00	0.86	−0.06	+0.38
Passeriformesorder	140	−0.13	−0.13	0.28	−0.13	−0.01
Artiodactylaorder	134	+0.08	−0.09	0.49	−0.02	+0.05
Cypriniformesorder	127	−0.08	−0.11	0.59	+0.04	−0.35
Carnivoraorder	123	−0.03	+0.02	0.85	−0.07	+0.24
Primatesorder	112	+0.06	+0.07	0.65	−0.03	+0.15
Rodentiaorder	87	+0.00	−0.02	0.99	+0.13	+0.02
Squamataorder	60	+0.11	+0.07	0.82	+0.00	−0.03
Charadriiformesorder	51	+0.09	+0.15	0.76	+0.05	+0.14
Testudinesorder	49	+0.22	+0.23	0.60	+0.02	−0.01
Psittaciformesorder	44	−0.54	−0.55	0.008 (significant)	−0.36	−0.29
Chiropteraorder	43	+0.13	+0.15	0.90	−0.09	+0.11
Clupeiformesorder	38	+0.18	+0.15	0.75	+0.00	–
Pleuronectiformesorder	35	+0.24	+0.22	0.39	−0.06	+0.22
Salmoniformesorder	35	−0.16	−0.13	0.71	−0.22	−0.43
Carcharhiniformesorder	31	+0.07	+0.03	0.88	−0.02	−0.34
Cetaceaorder	28	−0.13	+0.12	0.73	+0.13	−0.11
Anseriformesorder	25	−0.33	−0.34	0.43	−0.25	−0.24
Caudataorder	25	−0.14	+0.03	0.84	−0.04	–
Siluriformesorder	23	+0.38	+0.40	0.23	−0.01	–
Centrarchiformesorder	22	−0.20	−0.12	0.59	+0.01	–
Acipenseriformesorder	21	+0.64	+0.08	0.013 (significant)	+0.71	+0.39
Rajiformesorder	21	−0.18	−0.11	0.90	+0.31	–
Scombriformesorder	21	+0.44	−0.00	0.44	+0.36	–

n: species with both values in the group.
Pearson r, Spearman ρ: strength of the link with log₁₀ lifespan, from −1 to +1; Spearman uses ranks, so a few extreme species weigh less.
q: p-value adjusted for testing every mtDNA feature in the same group (Benjamini–Hochberg); rows with q < 0.05 are highlighted.
PIC r: the same test on phylogenetically independent contrasts, which removes similarity that comes from shared ancestry.
Partial r: the link with lifespan after accounting for body mass (log₁₀ adult weight), since bigger animals tend to live longer.

12S rRNA aligned across species

2,314 species, 3,496 columns; 939 columns have a residue in at least half of the species, and in 452 of those one residue is in 90% or more. MAFFT v7.526, FFT-NS-2 (progressive)

Loading the alignment of 12S rRNA: 2,314 species, 3,496 columns.

Nucleotide alignmentrRNA-12S.nt.fasta.gz · 2,314 rows · 660.5 KB

All alignment files