Vox Sang, 10: 738-741 (1965)

Minus-Minus (-I-) E, Ed Phenotypes and a New Allele Eeg ( =E7) in Pigs of the Hampshire Breed*

E . ANDRESEN Iowa State University, Ames, Iowa

The E blood group system in pigs was detected as a one-blood-factor, two-allele system [l]. Summaries of the emergence of this system have been reported [2, 71, and a comprehensive description was published in 1963 [3]. At that time 6 blood factors, Ee, E b , E d , Ee, Er, and E,, had been detected by reagents isolated from isoimmune sera. The blood factors Ea-Ed, Eb-Ee, and Er-Eg appeared to occur as 3 sets of reciprocal blood factors (closed systems) in each breed investigated. The possibility of a complicated E locus was considered [2, 31. How- ever, there is so far no exception to the assumption that the 5 anti- gens (= agglutinogens or phenogroups) Ebdg , Edeg, Eaeg, E d e f , and Ebdr arc inherited as products of allelic genes, El, Ea, E3, E4, and EG. A 6th allele, E 6 , and its corresponding antigen, Eaef, have been de- tected [6], and a newly discovered blood factor, E h , is controlled by the E and E alleles [5].

The inheritance of the Ea and E d factors is considered in this rcport. The Duroc and Hampshire pigs available for these investiga- tions originated from farms in Iowa [9]. The numbers of pigs tested with anti-Ea and anti-Ed are indicated in Tables I and 11. Most of these pigs were also tested with E b , Ec, Er, and E, reagents. An Eh reagent was not available. The blood collecting and serological tech- niques have been described previously [3, 41.

The phenotypic segregation of offspring typed with Ea and E d

reagents confirms published evidence [2, 3, 5, 6, 7, 81 that blood factors Ea and E d are inherited b y allelic genes (Table I). Moreover, the reciprocal relationship exhibited by E, and E d when Duroc pigs

* Journal Paper No. J-5108 of the Iowa Agricultural and Home Economics Experiment Station, Ames, Iowa. Project No. 1424. This work has received as- sistance from Contract AT(ll-1)-707 from the U. s. Atomic Energy Commission.

ANDRESEN 739

TABLE I

Inheritance of Blood Factors En and E d in the Duroc and Hampshire Breeds of Pigs

Breed

Matings Offspring phenotypes and numbers

Typez Number E. E.Ed Ed

Duroc

E, x En 9 74 - - En x EnEd 82 380 359 -

Hampshire En x Ed 74 - 645 -

EnEd x E,Ed 138 340 590 285 EnEd x Ed 218 63 942 951

E d x E d 90 - - 799

Phenotypic distribution of 4648 offspring from 498 Duroc matings (145 sires) and the distribution of 5371 offspring from 611 Hampshire matings (137 sires) tested with anti-En and anti-&.

’J Type abbreviations: E, = E(a+d-), Ed = E(a-df), and EnEd = E(a+d+). Offspring from 2 litters sired by 1 boar (matings 1 and 3 in Table 11).

are tested gives evidence for a closed “ E a E d system” within the E system in this breed. In other words, the evidence indicates that the three phenotypes observed in Durocs reflect the 3 genotypes EaEa, EaEd, and E d E d , if only tests with the Ea and Ed reagents are considered.

The 6 E(a-td-) phenotypes indicated in bold-faced type in Table I are exceptions to the assumption of a single pair of alleles in the Hampshire breed. These exceptions were observed among offspring in 2 litters from 2 E(a+d+) sows. Both litters were sired by the same E(a-d+) boar. This boar sired the 12 litters represented in Table I1 in which the numbers of exceptional phenotypes are indicated in bold- faced type. The 2 litters already considered correspond to matings 1 and 3 in that table. Four E(a+d-) offspring were observed in 2 addi- tional litters from the same parents, and there were 11 exceptions among offspring from 2 unrelated sows bred by tha t boar (matings

740 ANDRESEN Minus-Minus (-I-) E,Ed Phenotypes and

TABLE I1

Distribution of &-Ed Pheno6ypes Among Oflspring from an E(o-d +) Hampshire Boar (Genotype: EdbglE'g) and 10 Hampshire Sows

The data from matings No. 1, 3, 7 , 8 and 9 are included in Table I. Digits indicated in bold-faced type correspond to exceptions to the assumption of a closed EaEd system

Reactions of Sow's Offspring phenotypes and Mating Sow sow with alternative numbers

reagents for E - phenogroups' Ell Ed E(atd-) E(a-dt) E(a+d+) E(a-d-)

1 2 3 4 5 6 7 8 9

10 11 12

2095-161

2695-161

2902-261 3472-262 3994-261

456-160 3334-261 3140-262 4741-263 4742-263

-1-

- + +

-1-

I

4 4 2 1 5 5 2 9 3 3 6 1 6 0 9 5 0 4 0 12 0 0 9 0 0 10 0 0 7 2 2 4 0 0 1 0

0 0 0 0 0 0 u 0 0 0 1 4

_______ ~

' The loelis designation ( E ) is omitted.

5 and 6). Exceptional phenotypes were not found among offspring from matings 7-10. The boar was bred to 2 of his daughters (matings 11 and 12). Five E(a-d-) pigs were observed among a total of 12 pigs in the 2 litters.

The results in Table I1 could be explained by assuming that the boar had an allele for a weak Ea or Ed factor. Therefore, the 5 minus- minus phenotypes should have this allele in double dose, which is expected to cause a maximum amount of weak Ea or E(1 antigen or1 their erythrocytes. However, these 5 pigs were not only E, and E d negative by direct blood-typing, but they did not remove any anti-Ea or anti-Ed from the Ea and Ed reagents in absorptions.

The exceptions to the assumption of a closed E*Ed system in the Hampshire breed may be explained by assuming that the hetero- zygous boar (Table 11) had a hitherto undetected allele, E e g . The code designation E7 is proposed for this allele. I n double dose, E7 gives rise to a minus-minus phenotype, E(a-d-).

a New Allele EPR (= E7) in Pigs of the Hampshire Brecd 741

References

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5. HOJN+, J.: The erythrocytic antigens of pigs kept in CSSR. Thesis (The Czecho-

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8. SAISON, R. and INGRAM, D. G.: A report on blood groups in pigs. Ann. N. Y.

9. WILLHAM, R. L. and Cox, D. F.: Effect of paternal irradiation on 154 day

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Author's address: Dr. E. Andreucri, Antigenic Laburatury, Iuwa State University, Ames, Iowa (USA).