1)Can you suggest reasons why a phylogeny based on molecular evidence and a phylogeny
based on morphology and other evidence might not be exactly the same?
2) Zoologist worldwide are sequencing a mitochondrial gene CO1 (cyctochrome c oxidase
subunit), which is found in all animals and appears to be distinctive for each species. The
sequence of nucleotides can be used as a universal DNA bar code. By comparing the CO1 DNA
sequence for an animal to a growing database of DNA sequences, scientists can accurately
identify any animal and also discover species not previously known to science. How might DNA
bar coding, which uses molecular biology and bioinformatics, be useful in enforcing
international laws for banning the import of endangered species? How might these approaches
stimulate the study of biodiversity in remote areas?
1) The main reason why a phylogeny based on molecular evidence and a phylogeny based on morphology and other evidence might not be exactly the same is because they capture different aspects of an organism's evolutionary history.
Molecular evidence, such as DNA sequences, reflects the genetic relationships between organisms. It provides information about the genetic changes that have occurred over time and therefore can be used to infer common ancestry. On the other hand, morphology and other types of evidence, such as anatomical features or behavior, focus on observable characteristics of organisms. These traits can also provide insights into evolutionary relationships.
However, several factors can lead to discrepancies between the two types of phylogenies. Firstly, sometimes there can be convergent evolution, where different species independently evolve similar morphological features due to similar environmental pressures. This can create confusion when trying to determine common ancestry based solely on morphology.
Secondly, molecular evidence can uncover genetic similarities or differences that are not immediately apparent from morphology. For example, two organisms might appear very different but have similar DNA sequences, suggesting a closer evolutionary relationship. Conversely, two organisms might look very similar but have significant genetic differences, indicating a more distantly related ancestry.
Lastly, incomplete lineage sorting and horizontal gene transfer can also affect the congruence between molecular and morphological phylogenies. Incomplete lineage sorting occurs when ancestral genetic variation is not fully sorted out among descendant species, leading to different gene trees compared to the species tree. Horizontal gene transfer refers to the transfer of genetic material between non-related organisms, which can further complicate the relationship between molecular and morphological traits.
To address these discrepancies, scientists often integrate both molecular and morphological data to obtain a more comprehensive understanding of evolutionary relationships. This approach, known as phylogenetic synthesis, combines multiple lines of evidence to construct a more accurate phylogeny.
2) DNA barcoding, which utilizes molecular biology and bioinformatics techniques, can be highly useful in enforcing international laws for banning the import of endangered species. By comparing the CO1 DNA sequence of an animal to a database of known DNA sequences, scientists can accurately identify the species. This can aid in monitoring and regulating the trade of endangered species and their derivatives.
DNA barcoding provides a standardized and objective method for species identification, eliminating the need for relying solely on morphological characteristics that can be challenging to assess, especially for non-experts. It can also help to identify illegal wildlife products, such as exotic meats or traditional medicines derived from endangered species, which are often difficult to visually distinguish.
Furthermore, DNA barcoding can contribute to the study of biodiversity in remote areas. Traditional biodiversity surveys are often time-consuming and require field sampling and morphological identification skills. DNA barcoding allows for rapid species identification, even from small or degraded samples, and can help uncover new or cryptic species that might have gone unnoticed using traditional methods. This significantly enhances our understanding of biodiversity patterns and can inform conservation efforts in remote and understudied regions.
By combining DNA barcoding with other ecological and taxonomic research methods, scientists can gain better insights into the distribution, abundance, and conservation status of various species across different habitats, including remote areas. This knowledge is valuable for prioritizing conservation efforts, identifying key biodiversity areas, and implementing effective measures for the protection of endangered species.