The reproductive microbiome and maternal transmission via eggs in Sceloporus virgatus

Maternal transmission of microbes occurs across the animal kingdom and is vital for the  development and long-term health of offspring. The mechanisms of this transfer are most well studied in humans and other mammals, but are less well understood in egg-laying animals, especially in those with no parental care. Here we investigate the transfer of maternal microbes in Sceloporus virgatus, an oviparous spiny lizard. We compared three maternal tissue microbiomes – oviduct, cloaca, and intestine – to three offspring sample types: egg contents and eggshells on the day of oviposition, and hatchling intestinal tissue on the day of hatching. We found that dam ID is an important factor in hatchling microbiome composition, indicating that maternal transmission is occurring. The maternal cloacal and oviductal communities contribute to offspring microbiomes in all three sample types, but there was minimal influence of maternal intestinal microbes. This indicates that the maternal reproductive micr..., Sequences of the 16s V4 regions were generated at IIDS Genomics and Bioinformatics Resources Core at the University of Idahoon the Illumina MiSeq platform. Detailed methodology can be found in the attached README file., , # The reproductive microbiome and maternal transmission via eggs in Sceloporus virgatus

M. E. Bunker and S. L. Weiss

University of Puget Sound, 1500 N. Warner Street, Tacoma, WA, USA 98416-1088

## **Sample and Data collection**

Ten gravid female *Sceloporus virgatu*s were collected by lasso near the Southwestern Research Station in Cochise County, Arizona, on 26-27 June 2022. Animals were kept in 23 x 15 cm cages sterilized with 70% ethanol and had sterile water available ad libitum until 29 June, when they were induced to oviposit with a 0.1mL injection of oxytocin. Eggs were collected as they were laid and placed into individual cups of sterile vermiculite. For each female, the first and last egg was punctured with sterile scissors and the contents and shells were stored in separate 1.5ml microcentrifuge tubes (total of n = 20 per sample type). The remaining eggs (n = 78) were incubated until hatching at 30°C, either in sterile vermiculite or vermiculite treated with a single spec...