Many people are probably familiar with dinosaur eggs. A few years ago, a large number of dinosaur eggs were discovered in Xixia County, Henan Province, my country, and many were smuggled abroad by fossil traffickers; even more remarkably, some scholars claimed to have extracted dinosaur DNA (genetic material) from one of the eggs. For a time, dinosaur eggs became a hot topic of discussion in various newspapers, television stations, and radio stations.
Dinosaur eggs discovered in Xixia area
The discovery of a large number of dinosaur eggs in the Xixia area has indeed caused a great stir in the academic community and society. The fossil sites are spread across 15 townships and 57 villages in Xixia County and the neighboring Neixiang and Xichuan counties. Dinosaur bone fossils have also been discovered in 3 townships and 4 villages in Xixia and Neixiang counties. The area covered by dinosaur eggs and bone fossils reaches 8,578 square kilometers, with more than 5,000 dinosaur eggs unearthed. Such a large-scale discovery is truly a wonder of the world. These discoveries not only provide materials for the classification of dinosaurs and dinosaur eggs, but also offer a wealth of valuable information for further understanding dinosaur reproduction, paleogeography, paleoclimate, paleomorphology, paleoecology, stratigraphy, and taphonomy.
However, the report of extracting dinosaur DNA from a dinosaur egg was met with skepticism from many scientists from the outset. It is said that the egg from which the dinosaur DNA was extracted was accidentally broken during transport, and the contents of the eggshell were found to be a soft, flocculent substance, rather than the hard material composed of mudstone or sandstone typically found inside dinosaur eggs.
Therefore, researchers believed that this soft, flocculent substance was a product of the incomplete decomposition of organic matter such as the yolk and egg white from a dinosaur egg. Based on this, they conducted extraction work in a laboratory formerly used for plant biochemistry experiments, extracting a fragment of DNA. They then compared this DNA fragment with the DNA of some known plants and animals, and based on the different comparison results, announced that they had extracted DNA from a certain dinosaur.
What has raised suspicion among many scholars is whether those "soft, flocculent substances" are products of incomplete decomposition of organic matter such as egg yolk and egg white. It's important to understand that dinosaur eggs have been buried underground for at least 65 million years. Geologically, the strata containing the dinosaur egg fossils in the Xixia area consist of mudstone or siltstone, lacking the environmental factors necessary to effectively protect the organic matter from decomposition. Therefore, over such a long period, the original organic matter in the dinosaur eggs would have long since decomposed. The material inside the eggshell, through displacement processes over these long years, would be filled with minerals similar to those in the surrounding burial environment, and would have already petrified. Those "flocculent substances" are likely crystals formed from calcite minerals commonly found in the strata within the eggshell. If you visit the Paleozoological Museum of China, not far west of the Beijing Zoo, you can see a dissected dinosaur egg on the second floor; its interior is completely filled with calcite crystals, making it appear crystal clear. The egg's "softness" likely indicates it was soaked by groundwater while buried underground, or became moist after being unearthed due to water or a damp environment. Since the egg may have been waterlogged and is broken, it's highly probable it was contaminated with organic matter containing some kind of DNA. The fact that the extractors compared this DNA fragment with the DNA of known plants and animals, and declared it to be dinosaur DNA based on the comparison results, is unreliable. Only when this DNA fragment is compared with all known organisms and the results differ can you say it belongs to an extinct or undiscovered species. Their work is far from reaching that point.
Later, some scientists compared that so-called "dinosaur DNA fragment" with the DNA of many more organisms and found that its sequence was similar to that of a certain primitive algae!
The "dinosaur DNA" incident has now faded from the scientific community's memory, but normal research on dinosaur eggs continues unabated. Scientists have used modern instruments such as electron microscopes to conduct ultra-microscopic observations and chemical analyses of dinosaur eggshells, revealing that approximately 93% of the eggshell is calcium carbonate, consisting of an organic base layer and a calcite layer. This double-layered structure, similar to that of modern bird eggs, effectively prevents moisture evaporation, thus protecting the embryo and ensuring its normal development. This proves that dinosaurs could reproduce in extremely dry environments at that time.
In some dinosaur eggs unearthed in the Xixia region of my country and some areas of Mongolia, scientists have also discovered embryos or baby dinosaurs. This not only allows scientists to know which dinosaur laid these eggs, but also provides clues and evidence for them to explore the development of these dinosaurs.
Recently, Chinese scientists have also discovered eggshell lesions in dinosaur eggs found in Nanxiong, Guangdong and Laiyang, Shandong, providing new perspectives and evidence for the study of the extinction of dinosaurs.
As more dinosaur eggs are discovered and research continues, they will contribute to helping scientists unravel more mysteries of nature.
