The study by Palmer et al. investigates the development of the human infant intestinal microbiota, focusing on the temporal progression, sources, and variability of microbial communities in healthy, full-term infants. The researchers designed a microarray to detect and quantify small subunit ribosomal RNA (SSU rRNA) gene sequences of bacteria, profiling microbial communities from 26 stool samples each of 14 healthy infants over the first year of life. They also analyzed vaginal and milk samples from mothers and stool samples from parents and siblings to explore possible origins of the infant microbiota. Key findings include: - The composition and temporal patterns of microbial communities varied widely among infants, with distinct features recognizable for weeks to months. - The microbial communities of fraternal twins showed strikingly similar temporal patterns, suggesting that environmental factors play a major role in shaping the unique characteristics of each baby's microbiota. - By the end of the first year, the individual microbial ecosystems had converged toward a profile characteristic of the adult gastrointestinal tract. - The study highlights the importance of understanding the role of early environmental exposures in shaping the infant microbiota and the potential impact of these exposures on health and disease. The study provides a detailed reference for future research on the factors influencing the development of the infant gastrointestinal microbiota and its implications for human health.The study by Palmer et al. investigates the development of the human infant intestinal microbiota, focusing on the temporal progression, sources, and variability of microbial communities in healthy, full-term infants. The researchers designed a microarray to detect and quantify small subunit ribosomal RNA (SSU rRNA) gene sequences of bacteria, profiling microbial communities from 26 stool samples each of 14 healthy infants over the first year of life. They also analyzed vaginal and milk samples from mothers and stool samples from parents and siblings to explore possible origins of the infant microbiota. Key findings include: - The composition and temporal patterns of microbial communities varied widely among infants, with distinct features recognizable for weeks to months. - The microbial communities of fraternal twins showed strikingly similar temporal patterns, suggesting that environmental factors play a major role in shaping the unique characteristics of each baby's microbiota. - By the end of the first year, the individual microbial ecosystems had converged toward a profile characteristic of the adult gastrointestinal tract. - The study highlights the importance of understanding the role of early environmental exposures in shaping the infant microbiota and the potential impact of these exposures on health and disease. The study provides a detailed reference for future research on the factors influencing the development of the infant gastrointestinal microbiota and its implications for human health.