Related Experiment Video
Updated: Dec 23, 2025
04:52
Following the Dynamics of Structural Variants in Experimentally Evolved Populations
Published on: February 3, 2023
1.3K
Null hypotheses for developmental evolution.
Samuel H Church1, Cassandra G Extavour1,2
1Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA church@g.harvard.edu extavour@oeb.harvard.edu.
Development (Cambridge, England)
|April 29, 2020
Summary
Developmental biologists can define a null hypothesis for developmental evolution by analyzing extensive data across the tree of life. This approach challenges assumptions of rare change and increasing complexity in evolution.
Area of Science:
- Developmental Biology
- Evolutionary Biology
- Genomics
Background:
- Understanding the rate of evolutionary change in developmental processes is crucial.
- Previous assumptions about developmental evolution were based on limited data.
- The concept of a null hypothesis for developmental evolution is underdeveloped.
Purpose of the Study:
- To propose the definition of a null hypothesis for developmental evolution.
- To leverage current extensive developmental data for evolutionary insights.
- To re-evaluate prior assumptions regarding the rarity of developmental change.
Main Methods:
- Analysis of a large, diverse dataset of developmental biology information.
- Comparative analysis of developmental traits across the tree of life.
- Re-examination of existing evolutionary and developmental biology paradigms.
Main Results:
- Developmental biologists are well-positioned to establish a null hypothesis for developmental evolution.
- Unprecedented access to developmental data allows for deeper evolutionary analysis.
- Challenging the assumption that developmental change is rare is necessary.
Conclusions:
- A robust null hypothesis for developmental evolution can be formulated using current data.
- This framework will refine our understanding of evolutionary processes.
- It is essential to move beyond outdated assumptions about evolutionary optimization and complexity.
Related Concept Videos
01:49Hardy-Weinberg Principle
75.7K
Diploid organisms have two alleles of each gene, one from each parent, in their somatic cells. Therefore, each individual contributes two alleles to the gene pool of the population. The gene pool of a population is the sum of every allele of all genes within that population and has some degree of variation. Genetic variation is typically expressed as a relative frequency, which is the percentage of the total population that has a given allele, genotype or phenotype.
75.7K
01:16Null and Alternative Hypotheses
11.8K
The actual hypothesis testing begins by considering two hypotheses. They are termed the null hypothesis and the alternative hypothesis. These hypotheses contain opposing viewpoints.
The null hypothesis, denoted by H0 is a statement of no difference between the variables—they are not related. This can often be considered the status quo. As a result if you cannot accept the null, it requires some action.
The alternative hypothesis, denoted by H1 or Ha, is a claim about the...
The null hypothesis, denoted by H0 is a statement of no difference between the variables—they are not related. This can often be considered the status quo. As a result if you cannot accept the null, it requires some action.
The alternative hypothesis, denoted by H1 or Ha, is a claim about the...
11.8K
02:55The Evidence for Evolution
47.4K
Genetic variations accumulating within populations over generations give rise to biological evolution. Evolutionary changes can result in the formation of novel varieties and entire new species. These changes are responsible for the diverse forms of life inhabiting the planet. The evidence for evolution suggests that all living organisms descended from common ancestors.
47.4K
01:21Nondisjunction
4.6K
Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate correctly and move to the opposite poles of the cells. This produces daughter cells with abnormal chromosome numbers. Nondisjunction is common during anaphase I or anaphase II of meiosis. Mutations in synaptonemal complex proteins that attach homologous chromosomes increase the chances of nondisjunction in anaphase I of meiosis I. In contrast, mutations in topoisomerases and condensins that hold...
4.6K
01:29Nondisjunction
81.5K
During meiosis, chromosomes occasionally separate improperly. This occurs due to failure of homologous chromosome separation during meiosis I or failed sister chromatid separation during meiosis II. In some species, notably plants, nondisjunction can result in an organism with an entire additional set of chromosomes, which is called polyploidy. In humans, nondisjunction can occur during male or female gametogenesis and the resulting gametes possess one too many or one too few chromosomes.
81.5K
01:11Types of Hypothesis Testing
27.7K
There are three types of hypothesis tests: right-tailed, left-tailed, and two-tailed.
When the null and alternative hypotheses are stated, it is observed that the null hypothesis is a neutral statement against which the alternative hypothesis is tested. The alternative hypothesis is a claim that instead has a certain direction. If the null hypothesis claims that p = 0.5, the alternative hypothesis would be an opposing statement to this and can be put either p > 0.5, p < 0.5, or p...
When the null and alternative hypotheses are stated, it is observed that the null hypothesis is a neutral statement against which the alternative hypothesis is tested. The alternative hypothesis is a claim that instead has a certain direction. If the null hypothesis claims that p = 0.5, the alternative hypothesis would be an opposing statement to this and can be put either p > 0.5, p < 0.5, or p...
27.7K