A major goal of molecular evolutionary biology is to identify loci or regions of the genome under selection  . Correct identification allows further comprehension of the phenotypic changes responsible for adaptation and improves both our historical inference and predictive ability for understanding evolution from the past and into the future. To attain this goal, we need not only knowledge of the biological relevance of selective processes relative to neutral processes occurring in the genome, but also a concise and universal lexicon for discussing the relevant evidence. Neither selectionnor drift alone can explain levels of genomic diversity observed across the genome, emphasizing the importance of understanding how and when these disparate evolutionary forces may act. In fact, modern genomic insights have proven that more complex processes such as linkage, demography, and biased gene conversion further complicate our understanding of the roles of neutral versus selective processes in evolution. In this perspective, we aim to present and refine our definitions of selection and drift, as well as additional and important mechanisms that constrain evolution of the genome under certain contexts. We highlight that these processes need to be taken into account to correctly identify the targets of selection and stress that a major  field-wide goal in the future should be to quantify the absolute importance of these mechanisms.
A major goal of molecular evolutionary biology is to identify loci or regions of the genome under selection versus those evolving in a neutral manner . Correct identification allows accurate inference of the evolutionary process and thus comprehension of historical and contemporary processes driving phenotypic change and adaptation. A fundamental difficulty lies in distinguishing sites targeted by selection from both sites linked to these targets and sites fully independent of selection. These three categories of sites necessitate attention in light of the debate over the relative importance of selection versus neutrality and the neutral theory. Modern genomic insights have proved that complex processes such as linkage, demography, and biased gene conversion complicate our understanding of the role of neutral versus selective processes in evolution. In this perspective, we first highlight the importance of the genomic and (a)biotic context of new mutations to identify the targets of natural selection. We then present mechanisms that may constrain the evolution of genomes and bias the inference of selection. We discuss these mechanisms within the two critical levels that they occur: the population level and the molecular level. We highlight that they should be taken into account to correctly distinguish sites across the genome subject to selective or non-selective forces and stress that a major current field-wide goal is to quantify the absolute importance of these mechanisms.
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versus those evolving in a neutral manner
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further comprehension of the phenotypic changes responsible for adaptation and improves both our historical inference and predictive ability for understanding evolution from the past and into the future. To attain this goal, we need not only knowledge of the biological relevance of selective processes relative to neutral processes occurring in the genome, but also a concise and universal lexicon for discussing the relevant evidence. Neither selectionnor drift alone can explain levels of genomic diversity observed across the genome, emphasizing the importance of understanding how and when these disparate evolutionary forces may act. In fact, modern
accurate inference of the evolutionary process and thus comprehension of historical and contemporary processes driving phenotypic change and adaptation. A fundamental difficulty lies in distinguishing sites targeted by selection from both sites linked to these targets and sites fully independent of selection. These three categories of sites necessitate attention in light of the debate over the relative importance of selection versus neutrality and the neutral theory. Modern
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proven that more
proved that
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further
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roles
role
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aim to present and refine our definitions of selection and drift, as well as additional and important mechanisms that constrain evolution of the genome under certain contexts. We highlight that these processes need to
first highlight the importance of the genomic and (a)biotic context of new mutations to identify the targets of natural selection. We then present mechanisms that may constrain the evolution of genomes and bias the inference of selection. We discuss these mechanisms within the two critical levels that they occur: the population level and the molecular level. We highlight that they should
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identify the targets of selection
distinguish sites across the genome subject to selective or non-selective forces
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current
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in the future should be
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