# Survey of SNPs Associated with Total Number Born and Total Number Born Alive in Pig
## 3 SNPs Associated with Total Number Born  
In general, in Pig QTLdb for TNB showed 218 SNPs (as Genome map association), of which 155 SNPs were detected by [PERSON] et al. [8] and [PERSON] et al. [28] in Erhualians, 52 SNPs are defined in Large White, Yorkshire, Landrace, 1 SNP in Berkshire and 10 SNPs in Duroc (Table 2) [14; 18; 22; 23; 24; 25; 29; 30; 31; 32; 33]. SNPs associated with TNB are represented in all Sus Scrofa Chromosome except for SSCY. For an associative study [PERSON] et al. [8] selected Erhualan sows with high and low EBV values. According to the results of their work, the most significant SNPs were detected on SSC2 chromosomes (rs81367039), SSC7 (rs80891106), SSC8 (rs81399474), SSC12 (rs81434499), SSC14 (rs80938898). Among them SNPs on chromosomes SSC2, SSC7, and SSC12 were annotated for the first time. To study the effect of significant SNPs additional studies were conducted on a livestock of 331 Erhualan sows. According to the results of additional testing, significant differences in TNB were found only for SNP rs81399474 (SSC8). In the studies of [PERSON] et al. [28] 8 SNPs were identified as associated with TNB in Erhualian sows and located on SSC1, SSC4, SSC7, SSC8, SSC10, SSC12, SSC13 and SSC16. Studies of Large White pigs conducted by [PERSON] et al. [30] allowed the identification of 10 SNPs associated with the number of piglets at birth and located on SSC1, SSC5, SSC8, SSC11, SSC13 and SSC18. SNPs (rs80989787 and rs81289355) located on SSC11 were annotated for the first time in this paper. The most significant effect has been determined for SNP rs80989787 (SSC11). According to the results of associative studies conducted by [PERSON] et al. [18] on Finnish Landrace pigs 10 SNPs were identified. All established SNPs are located on SSC9. The most significant effect was established for SNP rs81300575 (SSC9), which amounted to about 1 piglet between two homozygous genotypes. In the studies of [PERSON] et al. [18] it was also noted that in the past 15 years the frequency of the desired SNP rs81300575 (SSC9) genotype in the studied population has increased from 0.14 to 0.22. [PERSON] et al. [29] conducted research on Duroc pigs and identified 10 SNPs associated with TNB. The most significant SNPs were rs80979042 and rs80825112 located on SSC14. In addition, the remaining potential SNPs were located on SSC5, SSC6, SSC12 and SSC17. In the studies of [PERSON] et al. [23], [PERSON] et al. [14], [PERSON] et al. [22] and [PERSON] et al. [25] the effects of SNPs on TNBs were investigated along with the search of SNPs associated with NBAs. So according to the results of [PERSON] et al. [23] the database contains 16 SNPs defined on SSC1, SSC2, SSC7, SSC14 and SSC18. [PERSON] et al. [14] established 5 SNPs associated with TNB located on SSC8 and SSC14. [PERSON] et al. [22] identified 11 SNPs for TNB on SSC1-SSC5, SSC13 and SSC18, and [PERSON] et al. [25] 2 SNPs (rs342908929 (SSC6) and rs324003968 (SSC15)). Besides this, Pig QTLdb presents SNPs associated with TNB according to the studies of [PERSON] et al. [31]--SNP rs81452018 SSC15, [PERSON] et al. [32]--SNP rs345476947 SSC6 and [PERSON] et al. [33]--rs rs55618224 SSC6. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**No** & **SNP** & **SSC** & **Location** & **Allele** & **Consequence** & **SYMBOL** & **T trait** & **Breed** & **Reference** \\ \hline  
21 & rs1330112 & 2 & 3058633 & A & upstream\_gene\_var & CTTN & TNB & Erhualian & [8] \\ \hline
22 & rs1214065 & 2 & 7420349 & A & missense\_variant & PYGM & TNB & Erhualian & [8] \\ \hline
23 & rs18474834 & 2 & 9252507 & T & intron\_variant & - & TNB & Erhualian & [8] \\ \hline \hline \end{tabular}
\end{table} 
Table 2: SNPs (Single nucleotide polymorphism) associated with TNB (Total number born alive) presented in the Pig QTLdb (Pig Quantitative Trait Locus Database). Ensembl db, Sus Scrofa 11.1 (NA—This variant has not been mapped on Ensembl db, Sus Scrofa 11.1).