Figure 2. Pup retrieval performance of WT in two strains and Mecp2^Het (Het) across days:

A-B) Left: WT mice retrieved significantly faster on D2-D5 compared to D0, as measured by latency index (A, p < 0.05, p < 0.01), and made few errors in all 6 days (B). Compared to WT, Het retrieved significantly slower (A, *p < 0.05) and made more errors (B, *p < 0.05, **p < 0.01) on D0 and D5. Compared to D0, Het showed significant behavioral improvement on D2–4 (A-B, p < 0.05, p < 0.01) and was indistinguishable from WT. Right: Average of all 6 days revealed Het retrieved significantly slower (A) and made more errors (B) compared to WT (**p < 0.01). N = 5–6 animals per genotype per day. C-D) Left: Both WT CBA and C57 mice showed behavioral improvement by retrieving pups faster throughout the 6-day test period compared to D0 (C, CBA D0 vs D#: p < 0.05, p < 0.01, p < 0.001; C57 D0 vs D5: p < 0.05). CBA and C57 also made fewer errors, with minimal but significant improvement on D2 and D4 by C57 compared to D0 (D, p < 0.05, p < 0.01). Right: on average, CBA behavioral performance was similar to C57 by latency index (C) and errors (D). N = 4 animals per genotype per day. For A-D, mean ± s.e.m. are shown. For A-D Right, each circle represents one animal. Statistics: Mann-Whitney test or Kruskal-Wallis followed by Dunn’s.