Final answer:
Testing gene versus species trees can be done by comparing genetic inheritance patterns to species divergence, conducting environmental swaps, comparing genetic codes, and analyzing the data for reproducibility and reliability of genetic information.
Step-by-step explanation:
To test the issue of gene versus species trees, a common approach involves comparing genetic inheritance patterns with observed species divergence. This can be done by investigating inheritance patterns in an organism like Wisconsin Fast Plants or Drosophila melanogaster through various genetic crosses. Researchers compare the expected phenotypic ratios, based on Mendelian inheritance, with those observed. If these do not match the species phylogeny, it could indicate events like horizontal gene transfer or hybridization that might complicate tree construction.
Another method includes environmental swaps where high-altitude and low-altitude plants are grown in each other's environments to observe whether their phenotypes converge, suggesting plasticity versus genetic fixity. Additionally, scientists can directly compare genetic codes from different species or exchange genes between them to study compatibility and survivability, providing insights into genetic similarities and potential ancestral gene flow. To conclude, data analysis of experiments, such as determining the amount of DNA produced by different fruits, is crucial to assess reproducibility and reliability of results, which feeds back into the understanding of gene and species relationships.