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Reprinted without change of paging from the Journal of Heredity (Organ of the American Genetic Association), Washington, D. C., Vol. XXXVII, No. 1, January, 1946.

THE "SNOWY BELLY" MOUSE

A Dominant Allele of the Agouti Series in the House Mouse

ORSON N. EATON and E. SCHWARZ
Washington, D. C.

FIVE alleles in the agouti series have been reported for the house mouse by various authors. They are described by Keeler.1 Another dominant allele in the series has been segregated in the progeny of a feral mouse, an adult male, which is the paternal ancestor of the strain described. This male was trapped in a shed in Arlington, Virginia, in May, 1941, and lived until March 25, 1943. Its skin and skull are now deposited in the United States National Museum, Washington, D. C. (no. 271008).

Its colors above is ochraceous, suffused with black. The back is very much lighter agouti than that of Aw or A, due to wider yellow banding of the hairs. The whole of the underside is pure white, the hairs being without dark roots. This includes the lower part of the cheeks, also the upper side of the hands to the wrists, and the upper side to the feet to the tarsal joints (hocks). There are a few speckled hairs in the middle line on the wrists and tarsal joints, and in an indistinct ochraceous throat mark. There is a clear ochraceous flank line that separates the sharply contrasted colors of the back and belly. The tail is distinctly bicolored, both the skin and the hairs, the lower side being unpigmented and covered with white hairs, even at the tip. The length of the head and body is 96 mm., that of the tail 90 mm., i.e., the tail is slightly shorter (tail ratio 107). 

This color pattern corresponds to that found in the wild strains of Mus musculus (wagneri, spicilegus, spretus), and the the Mediterranean and Middle Eastern feral mice (praetextus, bactrianus),

             TABLE I--Data on progeny of the snowy belly male

                     [[8 column table]]



F1 progeny             Number of progeny of the colors designated 

Type of mating | Snowy | Light* | Aw | Gray | Black | Other** | Total |
Snowy X AwAw  | 9 | 5 | 3  | - | - | - | 17 
Snowy X Aw-   | 2 | 1 | 2 | 1 | - | - | 6 
Snowy X A-    | - | - | - | 6 | - | - | 6 
Snowy X aa    | - | 3 | - | 12 | - | - | 15

F2 progeny

F1's from AwAw | 14 | 24 | 3 | 37 | - | - | 78  
F1's from Aw- | 5 | 6 | - | 8 | - | 10 | 29  
Snowy/Aw X Snowy/A | - | 2 | - | 4 | - | - | 6  
F1's from A- | 5 | 5 | - | 9 | - | 1 | 20  
F1's from aa | - | 4 | - | 11 | 4 | 7 | 26  

Backcross progeny

Snowy X F1's from Aw- | - |  6  | - |  7  | - | - |  13  
Snowy X F1's from A- | - | - | - |  1  | - | - |   1  
Snowy X F1's from aa |  1  |  4  | - |  9  | - | - |  14  
Snowy X F2's from AwAw |  9  |  6  | - | 14  | - | - |  29   
Snowy X F2's from Aw- | - |  2  | - | - | - | - |   2  
Snowy X F2's from aa |  1  |  8  | - |  6  | - | - |  15  
Snowy X later generations |  5  |  4  | - |  4  | - | - |  13  

F3 and later progenies

F2 and later generations | 456 | 140 | 10 | 152 | - | - | 758 

*These are generally lighter than Aw, not pure white like the male parent, but had a grayish underfur.

**Includes albinos and ce dilutes. This group was not considered in the F3 and later generations.

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Transcription Notes:
Not positive on the formatting for the transcription of the table. The numbers and headers are all there, though.