Fig. 4.

The number of clonal peaks in CDR3 spectratypes is reduced in old Labrador retrievers. (A) Matrix showing the number of peaks in individual CDR3 size spectratypes. Spectratypes with 8–10 peaks are shown in white, those with 5–7 peaks are in light grey, and those with ≤4 are shown in dark grey. (B) Dot plot showing the total number of peaks across all the CDR3 size spectratypes for each individual dog. Each dog is represented by a circle within their age group. A trend line (in black) is positioned at the median of each age group. The P value was calculated using a Mann Whitney U test comparing the two groups.