Supplementary Information

Supplementary Table 1. PCR-RFLP primers and conditions.

PCR reactions were carried out in 10μl total volume containing 10-20ng genomic DNA, 0.2mM dNTPs, 1.5mM MgCl2, 75mM Tris-HCl (pH 8.8), 20mM (NH4)SO4, 0.01% (v/v) Tween 20, 0.25u Taq DNA polymerase (Abgene) and each primer at 0.25-0.5μM.

A * in the primer sequence denotes a substitute nucleotide introduced to engineer a restriction endonuclease site. Restriction endonuclease digestion for each of the PCR products was carried out in standard conditions recommended by the manufacturer (New England Biolabs). Digestion products were run on agarose gels and visualised via ethidium bromide staining.

Polymorphism / Primers / Cycling conditions / Restriction endonuclease
(polymorphic base indicated in bold)
A-678G / C678f 5’-CGC-ACA-CCT-ATG-GTC-CCA-*GCT-3’
C678r 5’-AAG-CAG-AGG-AAC-CCG-GAA-AAT-GTC-3’ / 95ºc 5 min
95ºc 30 sec
64ºc 30 sec
72ºc 30 sec
72ºc 5 min / PvuII (CAG/CTG)
G666A / EXON2f 5’-AGT-GGT-TTC-CAC-AGT-CAG-AGC-3’
2EXON2r 5’-TCT-TCA-GCT-CGC-AGG-*TCA-A-3’ / 95ºc 5 min
95ºc 30 sec
52ºc 30 sec
72ºc 30 sec
72ºc 5 min / HincII (G*TY/RAC)
T5579C / Exon17f 5’ –AGA-GCA-CCA-ACC-ACC-CTG-T- 3’
Exon17r 5’ –AAA-GCT-GTC-TGT-GCT-TCT-GTG- 3’ / 95ºc 5 min
95ºc 30 sec
58ºc 30 sec
72ºc 30 sec
72ºc 5 min / MspI (C/CGG)

Supplementary Table 2. Tetra–primer ARMS-PCR.

PCR reactions were carried out in 10μl total volume containing 10-20ng genomic DNA, 0.2mM dNTPs, 1.5mM MgCl2, 75mM Tris-HCl (pH 8.8), 20mM (NH4)SO4, 0.01% (v/v) Tween 20, 0.25u Taq DNA polymerase (Abgene) and each primer at 0.5μM. An additional mis-match, denoted by * was incorporated into the A942-TC primer, to prevent it from annealing to the alternative allele.

Primers / Cycling conditions
942Ff 5’-GAC-AAA-ATA-GAG-GCA-CAA-GTT-AAG-3’
A942-TC 5’-GTT-TCC-ATA-TTG-TTT-GAA-TC*A-TAC- 3’
942+TC 5’-ATA-TTG-CTG-AAC-ATA-TTT-TGT-AAG-AGA-3’
S942Fr 5’-CAG-CCA-CAC-ATT-ATT-TTA-AAA-TTT-G-3’ / 95ºc 5 min
95ºc 30 sec
53ºc 30 sec
72ºc 30 sec
72ºc 5 min

Supplementary Table 3. Sequencing of –13.9kb region.

A 10μl PCR reaction was carried out containing 10-20ng genomic DNA, 0.5μM of each primer, 0.2mM dNTPs, 2.5mM MgCl2, 1 x Abgene. Thermostart reaction buffer, and 0.25u Thermostart Taq DNA polymerase (Abgene).

Primers / Cycling conditions
MCM6i13 5’-GGA-CAT-ACT-AGA-ATT-CAC-TGC-AAA-TAC-3’
MCM778 5’-CCT-GTG-GGA-TAA-AAG-TAG-TGA-TTG-3’ / 95ºc 5 min
95ºc 30 sec
54ºc 30 sec
72ºc 45 sec
72ºc 7 min
MCM6i13 5’-GGA-CAT-ACT-AGA-ATT-CAC-TGC-AAA-TAC-3’
LAC-CL2 5’-CTG-CTT-TGG-TTG-AAG-CGA-AGA-T-3’ / 95ºc 5 min
95ºc 30 sec
54ºc 30 sec
72ºc 30 sec
72ºc 5 min

Supplementary Table 4. Source references for Table 1 and for Table 4 of the main manuscript.

Holden & Mace (1997) extracted adults and also grouped data from the source references listed. See supplementary data Reference list for expanded references.

Population Group / Matched population group / Reference for numbers / Source Reference
Italians-south / Italians-south / Holden and Mace 1997 / De Ritis et al. 1970; Burgio et al. 1984; Cavalli-Sforza et al. 1987; Rinaldi et al. 1984
Israeli Arab / Jordanians (non-Bedouin) / Holden and Mace 1997 / Hijazi et al. 1983; Snook, Mahmoud, and Chang 1976
Palestinian Arab / Jordanians (non-Bedouin) / Holden and Mace 1997 / Hijazi et al. 1983; Snook, Mahmoud, and Chang 1976
Saudi Bedouin / Saudi Bedouin / Holden and Mace 1997 / Dissanyake, El-Munshid, and Al-Qurain 1990; Cook and al-Torki 1975
Jordanian Bedouin / Jordanian Bedouin / Holden and Mace 1997 / Hijazi et al. 1983
Israeli Bedouin / Jordanian Bedouin / Holden and Mace 1997 / Hijazi et al. 1983
Beni Amir / Beja, Beni Amir / Holden and Mace 1997 / Bayoumi et al. 1982
Jaali, Sudan / Jaali, Sudan / Bayoumi et al. 1981 / Bayoumi et al. 1981
Shaigi, Sudan / Shaygi, Sudan / Bayoumi et al. 1981 / Bayoumi et al. 1981
Dounglawi. Sudan / Dongolawi, Sudan / Bayoumi et al. 1981 / Bayoumi et al. 1981
Fulani pastoralist, Cameroon / Fulani pastoralist, Nigeria / Holden and Mace 1997 / Kretchmer et al. 1971

References for Supplementary information

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  2. Bayoumi RA et al (1981) Distribution of the lactase phenotypes in the population of the Democratic Republic of the Sudan. Hum.Genet. 57 (3):279-281.
  3. Cook GC and Al-Torki MT (1975) High intestinal lactase concentrations in adult Arabs in Saudi Arabia. Br.Med.J. 3 (5976):135-136.
  4. Cuddenec Y, Delbruck H, and Flatz G (1982) Distribution of the adult lactase phenotypes--lactose absorber and malabsorber--in a group of 131 army recruits. Gastroenterol.Clin.Biol. 6 (10):776-779.
  5. De RF et al (1970) High frequency of lactase activity deficiency in small bowel of adults in the Neapolitan area. Enzymol.Biol.Clin.(Basel) 11 (3):263-267.
  1. Dissanyake AS, El-Munshid HA, and Al-Qurain A (1990) Prevalence of primary adult lactose malabsorption in the eastern provine of Saudi Arabia. Annals of Saudi Medicine 10:598-601.
  2. Flatz G (1987) Genetics of lactose digestion in humans. Adv.Hum.Genet. 16:1-77.
  3. Harvey CB et al (1998) Lactase haplotype frequencies in Caucasians: association with the lactase persistence/non-persistence polymorphism. Ann.Hum.Genet. 62 ( Pt 3):215-223.
  4. Hijazi SS et al (1983) Distribution of Adult Lactase Phenotypes in Bedouins and in Urban and Agricultural Populations of Jordan. Tropical and Geographical Medicine 35 (2):157-161.
  5. Holden C and Mace R (1997) Phylogenetic analysis of the evolution of lactose digestion in adults. Hum.Biol. 69 (5):605-628.
  6. Kretchmer N et al (1971) Intestinal absorption of lactose in Nigerian ethnic groups. Lancet 2 (7721):392-395.

12. Snook CR, Mahmoud JN, and Chang WP (1976) Lactose tolerance in adult Jordanian Arabs. Trop.Geogr.Med. 28 (4):333-335.