Limulus polyphemus
Horseshoe crab
GC content
32.43%
Whole genome
Non-coding
371 bp
Including the D-loop
Where Horseshoe crab sits among 2,335 species
Whole-genome GC content against maximum lifespan. Horseshoe crab has the 910th longest lifespan of them.
- This species
- All other species
Base composition
Whole genome14,985 bp
- GC skew (G − C) / (G + C)
- −0.399
- AT skew (A − T) / (A + T)
- +0.111
About this record
- Lifespan source
- SeaLifeBase v26.06
- Based on
- an animal in the wild
- Data quality
- acceptable
- Licence
- CC BY-NC 4.0
- Status
- New in build 2
- In the database since
- build 2 (2026-11-13)
The lifespan value is for non-commercial use only; the genome data is not restricted by it.
Every change against the 2015 build is in the changelog download.
Composition by region
Reference (L) strand as deposited in RefSeqWhole genome14,985 bp
Protein-coding11,061 bp
12S rRNA799 bp
16S rRNA1,296 bp
All tRNA1,466 bp
Genes and regions
Select a column to sort; select a gene to compare it across species| Composition | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| ND1NADH dehydrogenase subunit 1 | 933 bp | 33.76% | −0.511 | +0.388 | |||||
| ND2NADH dehydrogenase subunit 2 | 1,017 bp | 31.56% | −0.570 | −0.052 | |||||
| COX1Cytochrome c oxidase subunit I | 1,536 bp | 37.89% | −0.210 | −0.044 | |||||
| COX2Cytochrome c oxidase subunit II | 685 bp | 35.77% | −0.331 | +0.036 | |||||
| ATP8ATP synthase F0 subunit 8 | 156 bp | 27.56% | −0.721 | +0.097 | |||||
| ATP6ATP synthase F0 subunit 6 | 675 bp | 34.37% | −0.526 | −0.029 | |||||
| COX3Cytochrome c oxidase subunit III | 784 bp | 38.65% | −0.333 | −0.073 | |||||
| ND3NADH dehydrogenase subunit 3 | 345 bp | 30.44% | −0.524 | −0.042 | |||||
| ND4LNADH dehydrogenase subunit 4L | 300 bp | 29.33% | −0.636 | +0.217 | |||||
| ND4NADH dehydrogenase subunit 4 | 1,338 bp | 31.91% | −0.485 | +0.374 | |||||
| ND5NADH dehydrogenase subunit 5 | 1,714 bp | 29.93% | −0.396 | +0.319 | |||||
| ND6NADH dehydrogenase subunit 6 | 462 bp | 30.30% | −0.629 | −0.006 | |||||
| CYTBCytochrome b | 1,132 bp | 35.78% | −0.427 | −0.081 | |||||
| 12S rRNA12S ribosomal RNA | 799 bp | 30.29% | −0.331 | +0.145 | |||||
| 16S rRNA16S ribosomal RNA | 1,296 bp | 29.01% | −0.447 | +0.148 |
Codon usage
Counts per codon, darker is more frequent3,691 codons in all protein-coding genes. Grouped with the Invertebrate mitochondrial code (NCBI table 5).
Phe F9.0%
UUU246
UUC85
Leu L15.4%
UUA226
UUG84
CUU106
CUC55
CUA94
CUG4
Ile I9.4%
AUU241
AUC107
Met M5.8%
AUA171
AUG43
Val V6.0%
GUU90
GUC14
GUA82
GUG36
Ser S10.5%
UCU110
UCC65
UCA98
UCG6
AGU22
AGC8
AGA66
AGG12
Pro P4.1%
CCU69
CCC27
CCA52
CCG4
Thr T4.8%
ACU53
ACC40
ACA84
ACG2
Ala A4.8%
GCU76
GCC39
GCA55
GCG6
Tyr Y3.3%
UAU87
UAC34
His H2.1%
CAU37
CAC41
Gln Q1.8%
CAA52
CAG15
Asn N4.0%
AAU103
AAC44
Lys K2.3%
AAA66
AAG19
Asp D1.6%
GAU36
GAC24
Glu E2.4%
GAA64
GAG23
Cys C1.3%
UGU40
UGC9
Trp W3.0%
UGA94
UGG17
Arg R1.7%
CGU14
CGC7
CGA34
CGG7
Gly G6.4%
GGU41
GGC21
GGA109
GGG66
Stop 0.2%
UAA7
UAG2
Genome map
37 annotated features in NC_003057.1Hover, tap or tab to a feature to see its position, length, strand and GC content. Genes and rRNAs open their own pages.
- Protein-coding13
- rRNA2
- tRNA22
- Outer ring: + strand, arrows run clockwise. Inner ring: − strand.
- Middle ring: GC% of each gene against the whole genome (32.4%, dashed): out is GC-richer, in is AT-richer (full height = 6 points).
All 37 features as a table
| Feature | Type | Start | End | Length | Strand | GC |
|---|---|---|---|---|---|---|
| COX1 | Protein-coding gene | 1 | 1,536 | 1,536 bp | + | 37.9% |
| COX2 | Protein-coding gene | 1,540 | 2,224 | 685 bp | + | 35.8% |
| tRNA-Lys | Transfer RNA | 2,225 | 2,294 | 70 bp | + | – |
| tRNA-Asp | Transfer RNA | 2,295 | 2,359 | 65 bp | + | – |
| ATP8 | Protein-coding gene | 2,360 | 2,515 | 156 bp | + | 27.6% |
| ATP6 | Protein-coding gene | 2,509 | 3,183 | 675 bp | + | 34.4% |
| COX3 | Protein-coding gene | 3,183 | 3,966 | 784 bp | + | 38.7% |
| tRNA-Gly | Transfer RNA | 3,967 | 4,030 | 64 bp | + | – |
| ND3 | Protein-coding gene | 4,031 | 4,375 | 345 bp | + | 30.4% |
| tRNA-Ala | Transfer RNA | 4,375 | 4,441 | 67 bp | + | – |
| tRNA-Arg | Transfer RNA | 4,445 | 4,507 | 63 bp | + | – |
| tRNA-Asn | Transfer RNA | 4,507 | 4,573 | 67 bp | + | – |
| tRNA-Ser (AGY) | Transfer RNA | 4,574 | 4,637 | 64 bp | + | – |
| tRNA-Glu | Transfer RNA | 4,638 | 4,703 | 66 bp | + | – |
| tRNA-Phe | Transfer RNA | 4,702 | 4,767 | 66 bp | − | – |
| ND5 | Protein-coding gene | 4,768 | 6,481 | 1,714 bp | − | 29.9% |
| tRNA-His | Transfer RNA | 6,482 | 6,550 | 69 bp | − | – |
| ND4 | Protein-coding gene | 6,552 | 7,889 | 1,338 bp | − | 31.9% |
| ND4L | Protein-coding gene | 7,883 | 8,182 | 300 bp | − | 29.3% |
| tRNA-Thr | Transfer RNA | 8,185 | 8,250 | 66 bp | + | – |
| tRNA-Pro | Transfer RNA | 8,252 | 8,318 | 67 bp | − | – |
| ND6 | Protein-coding gene | 8,322 | 8,783 | 462 bp | + | 30.3% |
| CYTB | Protein-coding gene | 8,783 | 9,914 | 1,132 bp | + | 35.8% |
| tRNA-Ser (UCN) | Transfer RNA | 9,915 | 9,987 | 73 bp | + | – |
| ND1 | Protein-coding gene | 9,997 | 10,929 | 933 bp | − | 33.8% |
| tRNA-Leu (UUR) | Transfer RNA | 10,930 | 10,995 | 66 bp | − | – |
| tRNA-Leu (CUN) | Transfer RNA | 10,996 | 11,064 | 69 bp | − | – |
| 16S rRNA | Ribosomal RNA | 11,065 | 12,360 | 1,296 bp | − | 29.0% |
| tRNA-Val | Transfer RNA | 12,361 | 12,429 | 69 bp | − | – |
| 12S rRNA | Ribosomal RNA | 12,430 | 13,228 | 799 bp | − | 30.3% |
| tRNA-Ile | Transfer RNA | 13,577 | 13,643 | 67 bp | + | – |
| tRNA-Gln | Transfer RNA | 13,642 | 13,707 | 66 bp | − | – |
| tRNA-Met | Transfer RNA | 13,707 | 13,776 | 70 bp | + | – |
| ND2 | Protein-coding gene | 13,777 | 14,793 | 1,017 bp | + | 31.6% |
| tRNA-Trp | Transfer RNA | 14,792 | 14,859 | 68 bp | + | – |
| tRNA-Cys | Transfer RNA | 14,859 | 14,922 | 64 bp | − | – |
| tRNA-Tyr | Transfer RNA | 14,924 | 5 | 67 bp | − | – |