Erythrocyte Count in Four Inbred Strains of Mice

Abstract

Since wide variation in the erythrocyte count for adult mice (Mus musculus) appears in the literature, the problem of whether this variation is genetic arose. It also seemed desirable to establish a mean red cell count on a more adequate number of animals than usually reported.

The figures given by various authors for erythrocyte counts (in millions per cu. mm.) are as follows: Simmonds, 1 6 to 8; Mixter and Hunt, 2 9.7 for “non-flexed” based on 12 animals and 11.2 for “flexed” based on 16 animals; Kamenoff, 3 9.9 for “non-flexed” based on 13 and 10.9 for “flexed” based on 5. The following figures are summarized from Scarborough 4 (in millions per cu. mm.): The work here reported was done in the laboratory of Dr. E. C. MacDowell of the Department of Genetics of the Carnegie Institution of Washington for which the author wishes to thank Dr. MacDowell, as well as for the use of his inbred mice strains.

The blood counts were made on samples of blood drawn from the tip of the tail and diluted 2, 3, or 4 to 1,000. Usually. 2 counts were made from a single sample from each mouse. The mice were adult breeding stock in good condition and from 6 weeks to one year old. They were from 4 of the highly inbred strains maintained at the Carnegie Institution laboratory in Cold Spring Harbor. Each strain had been brother-sister inbred for over 30 generations, and were thus highly homozygous. The strains used were, first, an albino strain known as Bagg Albino (B. Alb.); second, a dilute brown strain (d. br.); third, a black strain known as C 58 (the strain used extensively by Dr. MacDowell in his leukemia work); and fourth, a pink eye dilute brown strain known as Storrs-Little (Sto-Li).