Name: genetic drift simulation and hardy-weinberg lab prep
Uploaded: 2019-01-31T09:26:08.000Z
Duration: 1 min 53 s
Channel: JoVE

K12 Standards

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

9-12

Biology

Evolution

Mechanisms

Hardy-Weinberg and Genetic Drift

<ul><li><a href="#" data-time="7">Modelado Matemático
</a></li><li><a href="#" data-time="21">Simulación para Hardy-Weinberg y la deriva genética
</a></li></ul>

<ul class="lab-items"><li data-lab-item="1">
								<div class="ingrediente" data-value="Cuentas de colores (cada color, 10 colores diferentes)">Cuentas de colores (cada color, 10 colores diferentes)</div>
								<div class="cantidad-de-ingrediente">
									<span class="amount" data-value="500">500</span>
									<span class="unit" data-value=""></span>
								</div>
							</li><li data-lab-item="1">
								<div class="ingrediente" data-value="Portátil con capacidad para hoja de cálculo">Portátil con capacidad para hoja de cálculo</div>
								<div class="cantidad-de-ingrediente">
									<span class="amount" data-value="5">5</span>
									<span class="unit" data-value=""></span>
								</div>
							</li><li data-lab-item="1">
								<div class="ingrediente" data-value="Bolsa de papel">Bolsa de papel</div>
								<div class="cantidad-de-ingrediente">
									<span class="amount" data-value="5">5</span>
									<span class="unit" data-value=""></span>
								</div>
							</li><li data-lab-item="1">
								<div class="ingrediente" data-value="Recipientes de plástico extra para abalorios">Recipientes de plástico extra para abalorios</div>
								<div class="cantidad-de-ingrediente">
									<span class="amount" data-value="5">5</span>
									<span class="unit" data-value=""></span>
								</div>
							</li><li data-lab-item="1">
								<div class="ingrediente" data-value="Plato de papel">Plato de papel</div>
								<div class="cantidad-de-ingrediente">
									<span class="amount" data-value="5">5</span>
									<span class="unit" data-value=""></span>
								</div>
							</li></ul>

hardy-weinberg y la deriva genética

<ol class="note-items">
	<li data-note-item="1" data-parent-collapse="">Modelado Matemático<botón class="expandir">Expandir</button>
	<ul class="lab-items">
		<li data-sub-note-item="1-1">
		<div class="lab-step">Antes de comenzar el ejercicio de modelado matemático, asegúrese de que cada computadora tenga acceso a un programa de software de hoja de cálculo en línea o fuera de línea.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="2" data-parent-collapse="">Simulación para Hardy-Weinberg y la deriva genética<button class="expandir">expandir</button>
	<ul class="lab-items">
		<li data-sub-note-item="2-1">
		<div class="lab-step">Prepare un juego de cuentas para cada par de estudiantes contando 50 de un color y luego 50 de un segundo color, para un total de 100 cuentas.</div>
		</li>
		<li data-sub-note-item="2-2">
		<div class="lab-step">Luego, coloca las cuentas en una bolsa de papel.</div>
		</li>
		<li data-sub-note-item="2-3">
		<div class="lab-step">Los estudiantes también necesitarán cuentas adicionales para ajustar la composición de la población y estas se pueden proporcionar en un contenedor conjunto para toda la clase o los instructores pueden hacer conjuntos adicionales para cada par de estudiantes.</div>
		</li>
		<li data-sub-note-item="2-4">
		<div class="lab-step">A continuación, crea trozos de papel y escribe sobre ellos los diferentes escenarios experimentales que pondrán a prueba las violaciones del Equilibrio de Hardy-Weinberg.</div>
		</li>
		<li data-sub-note-item="2-5">
		<div class="lab-step">Luego, crea un segundo conjunto de hojas de papel para determinar qué escenario de deriva genética probarán los estudiantes.</div>
		</li>
		<li data-sub-note-item="2-6">
		<div class="lab-step">Finalmente, establece las cuentas adicionales necesarias para los escenarios experimentales enumerados en las tiras.</div>
		</li>
		<li data-sub-note-item="2-7">
		<div class="lab-step">NOTA: Se necesitarán 50 cuentas adicionales en un tercer color para la violación de la mutación, y un juego adicional de 100 cuentas en los dos primeros colores para el escenario de flujo de genes. Para simular el efecto fundador con 10 alelos y el desastre natural con 10 alelos, seleccione al azar 100 cuentas de 10 colores diferentes.</div>
		</li>
	</ul>
	</li>
</ol>

<div class="sección-pregunta"><h4 class="pregunta-sección">¿Qué es el principio de Hardy-Weinberg y por qué es útil?</h4><p>El principio de Hardy-Weinberg establece que, en ausencia de evolución, las frecuencias alélicas de una población permanecerán iguales a lo largo de las generaciones. Este principio se utiliza como modelo nulo para la genética de poblaciones y permite a los científicos comprender los mecanismos evolutivos.
</p></div><div class="sección-pregunta"><h4 class="pregunta-sección">¿Cómo se calcula el equilibrio de Hardy-Weinberg?...

Hardy-Weinberg y la deriva genética


Modelado MatemáticoExpandir
	
Antes de comenzar el ejercicio de modelado matemático, asegúrese de que cada computadora tenga acceso a un ...

Education

Educación

JoVE Lab Manual

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Evolución

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Subartículos del Manual de Laboratorio

genetic drift simulation and hardy-weinberg lab prep

<p class="jove_content">Genetic drift simulation and Hardy-Weinberg lab prep use beads and spreadsheet software to model changes in allele frequencies. Before starting the mathematical modeling exercise, make sure each computer has access to either online or offline spreadsheet software.</p>

<p class="jove_content">For the simulation, prepare one set of beads for each pair of students. Count out 50 beads of one color and 50 beads of a second color for a total of 100 beads, and place them in a paper bag. Students will also need extra beads to adjust the population makeup, and those can be kept in a shared class container or set up as additional bead sets for each pair.</p>

<p class="jove_content">Next, create paper slips that list the experimental scenarios used to test violations of Hardy-Weinberg equilibrium. Make a second set of slips to choose which genetic drift scenario the students will test. Set out any extra beads needed for those scenarios. A mutation violation needs 50 additional beads in a third color, and a gene flow scenario needs an extra set of 100 beads in the first two colors.</p>

<p class="jove_content">For the founder effect with 10 alleles and the natural disaster with 10 alleles, randomly select 100 beads from 10 different colors. This setup lets students compare how different population changes affect the model during the Hardy-Weinberg and genetic drift activity.</p>

Genetic Drift Simulation and Hardy-Weinberg Lab Prep

genetic-drift-simulation-and-hardy-weinberg-lab-prep

hardy-weinberg and genetic drift

Allele Frequency Shifts in Small Populations

Allele frequency shifts in small populations can be explored with the Hardy-Weinberg equation and genetic drift. In this activity, students model how dominant and recessive alleles change from one generation to the next. They use both a spreadsheet simulation and a bead-based lab to track those changes over time.<br /><br />The spreadsheet model begins with p, the frequency of allele A, and q, the frequency of allele B. Students enter starting values, then use random formulas and a concatenate function...

Genetic drift simulation and Hardy-Weinberg lab prep use beads and spreadsheet software to model changes in allele frequencies. Before starting the mathematical modeling exercise, make sure each computer has access to either online or offline spreadsheet software.<br /><br />For the simulation, prepare one set of beads for each pair of students. Count out 50 beads of one color and 50 beads of a second color for a total of 100 beads, and place them in a paper bag. Students will also need extra beads to...

lab manual sub articles

Set up a Hardy-Weinberg and genetic drift simulation with beads, paper slips, and spreadsheet software. Includes mutation, gene flow, founder effect, and natural disaster scenarios.

Genetic Drift Simulation and Hardy-Weinberg Lab Prep | JoVE K12

Next Generation Science Standards

High School

Life Science

heredity-inheritance-and-variation-of-traits

Heredity: Inheritance and Variation of Traits

HS-LS3-3

Florida Department of Education

SC.912.L.15

SC.912.L.15.12

SC.912.L.15.14

new-york-state-science-learning-standards

New York State Science Learning Standards

Inheritance and Variation of Traits

HS-LS3-3.

Natural Selection and Evolution

HS-LS4-1.

HS-LS4-3.

Georgia Standards of Excellence

SB6.d

<p>Los científicos alguna vez se preguntaron por qué los rasgos dominantes, como las manchas de jirafa de color bronceado, no se vuelven más frecuentes con cada generación y reemplazan a los rasgos recesivos como las manchas marrones oscuras. Al pensar en este enigma, en 1908, Godfrey H. Hardy y Wilhelm Weinberg derivaron independientemente una teoría, hoy conocida como el Principio de Hardy-Weinberg y representada por esta ecuación. </p>
<p>El principio establece que en ausencia de evolución, es decir, en equilibrio, las frecuencias alélicas y genotípicas de una población permanecerán constantes de una generación a la siguiente. Para entender esta ecuación, volvamos al ejemplo de la jirafa. La A mayúscula representa el alelo tostado ya que es dominante, y la A minúscula es para el alelo marrón porque es recesivo. La frecuencia de estos dos alelos en la población se designa como p y q respectivamente. Entonces, ¿cómo sabemos la frecuencia alélica? Bueno, cada individuo tiene dos alelos. En este ejemplo, el 40% de los alelos del acervo genético son bronceados. Por lo tanto, la frecuencia del alelo tan, p, es 0,4, y la frecuencia del alelo marrón, q, es 0,6. Nótese que p más q siempre es igual a uno. </p>
<p>Ahora volvamos a la ecuación de Hardy-Weinberg. Cada término de la ecuación representa una frecuencia de genotipo. La frecuencia del genotipo homocigoto dominante es p al cuadrado, y el homocigoto recesivo se representa mediante q al cuadrado. El genotipo heterocigoto es de dos pq. La razón por la que multiplicamos por dos aquí es que hay dos formas diferentes de generar un genotipo heterocigótico. Combinados, todos ellos representan el 100% de los genotipos. Por lo tanto, una frecuencia total de uno. Usando los valores de p y q de nuestro ejemplo de jirafa, podemos determinar la distribución genotípica de los alelos del gen de color en nuestra población de jirafas. Por lo tanto, según el principio de Hardy-Weinberg, en equilibrio, el 16% de la población de jirafas será homocigota dominante, el 48% será heterocigota y el 36% será homocigota recesiva. </p>
<p>Para mantener este equilibrio, el Principio de Equilibrio de Hardy-Weinberg establece que una población debe cumplir cinco supuestos principales. Debe haber apareamiento aleatorio, gran tamaño de la población, sin mutación, sin selección en el gen en cuestión y sin flujo de genes dentro o fuera de la población. La mayoría de las poblaciones naturales violan al menos uno de estos supuestos y, por lo tanto, el equilibrio es raro... pero a pesar de esto, el principio se utiliza como un modelo nulo para la genética de poblaciones. Al comparar estos valores esperados con la frecuencia real del genotipo en una población, se puede determinar si esa población está en equilibrio de Hardy-Weinberg. Si no es así, significa que se está produciendo algún tipo de evolución o cambio en la frecuencia alélica. </p>
<p>Un concepto erróneo general sobre la evolución es que requiere de la selección natural para ocurrir. Sin embargo, no siempre es así. La deriva genética es un mecanismo por el cual la evolución puede ocurrir sin selección natural. Se define como un cambio en la frecuencia alélica de una población debido al azar. Para imaginar esto, volvamos al ejemplo de una población de jirafas e imaginemos que sus alelos de color canela y marrón están representados por canicas de dos colores diferentes. Asumiremos aquí que cada color comienza siendo igualmente abundante. Si fuéramos a comenzar una nueva generación a partir de esta población, necesitaríamos criar pares de individuos y, por lo tanto, seleccionar entre cuatro alelos por par. Si seleccionamos una pareja reproductora al azar, entonces podríamos terminar con dos canicas de cada color. Sin embargo, solo por casualidad, algunos emparejamientos tendrán solo un color de mármol, o tres de un color y uno del otro. Estas desviaciones fortuitas de 50-50 en múltiples emparejamientos para crear una nueva generación podrían significar que la próxima generación ya no tiene una mezcla igual de cada alelo. </p>
<p>Es esta variación de las frecuencias alélicas relativas a lo largo del tiempo lo que define la deriva genética. Por lo tanto, a diferencia de la evolución adaptativa, donde la frecuencia alélica cambia para seleccionar rasgos que son adecuados para el medio ambiente, como las mariquitas con una mayor cantidad de melanina que sobreviven mejor en climas más fríos debido a una mayor capacidad para absorber calor, la deriva genética representa un tipo de evolución que se debe puramente al cambio estocástico. Por ejemplo, la eliminación aleatoria de una sección de una población a través de un evento catastrófico. </p>
<p>En este laboratorio, realizará simulaciones por computadora y de cuentas de colores del equilibrio de Hardy-Weinberg y la deriva genética en una población, y luego probará qué sucede cuando se violan las suposiciones del equilibrio.</p>

hardy-weinberg tests for population change

<p class="jove_content">Hardy-Weinberg tests help scientists check whether a population is changing over time. Because evolution happens slowly and over large areas, researchers often use mathematical models to study it. These models use measurable data and computer simulations to predict how allele frequencies may shift across many generations.</p>

<p class="jove_content">The Hardy-Weinberg equilibrium equation is one common model. It was developed independently in 1908 by G. H. Hardy and Wilhelm Weinberg. The equation gives the expected allele frequency for a population that is not evolving, so it serves as a useful null hypothesis. If measured allele frequencies do not match the prediction, the gene may be undergoing evolutionary change.</p>

<p class="jove_content">The model is written as p2 + 2pq + q2 = 1. In this equation, p is the frequency of the dominant allele and q is the frequency of the recessive allele. The three terms represent the expected frequencies of the three diploid genotypes: homozygous dominant, heterozygous, and homozygous recessive. The allele version of the model is p + q = 1, since the two allele frequencies must total 1 in the population.</p>

<p class="jove_content">Hardy-Weinberg also depends on a set of assumptions. The population must be very large and closed, which means no individuals move in or out. There must be no mutations in the gene being studied. Individuals must mate at random, and natural selection must not be acting. When real data breaks one or more of these assumptions, the model can help point to what may be happening.</p>

<p class="jove_content">Genetic drift is one reason a small population can change by chance alone. This violates the large-population assumption of Hardy-Weinberg. One form of genetic drift is the founder effect. It happens when a small group leaves and starts a new isolated population. The genes carried by those founders shape future generations. In an extreme case, if the founders are all homozygous recessive, the dominant allele can disappear and the recessive allele can reach 100%.</p>

<p class="jove_content">A similar pattern is called the bottleneck effect. It can occur after a natural disaster, human intervention, or disease causes a major drop in population size. Genetic drift is not necessarily adaptive, because it does not specifically favor traits that fit the environment. Even so, it is an important evolutionary force in small populations and can create differences from Hardy-Weinberg predictions. In larger populations, those differences are more likely to suggest natural selection.</p>

<p class="jove_content">Scientists also use Hardy-Weinberg testing in modern studies of human and animal populations. One focus is how immune system genes relate to susceptibility to infectious disease. Researchers study genes such as CCR5 and the major histocompatibility complex, or MHC, called HLA in humans. By comparing genetic data with disease data, they can find patterns showing that some individuals are more resistant to certain infections while others are more likely to become ill. These studies have helped explain how infections have influenced evolution.</p>

Hardy-Weinberg Tests for Population Change

El cambio evolutivo es interesante e importante de estudiar, pero los cambios en las poblaciones ocurren durante largos períodos de tiempo y en enormes espacios físicos y son ...

hardy-weinberg-tests-for-population-change

Pruebe su comprensión de Hardy-Weinberg y la deriva genética con este cuestionario de evaluación de Biology en JoVE Lab Manual. Cubre conceptos clave a través de preguntas basadas en video diseñadas para evaluar el aprendizaje de los estudiantes.

Hardy-Weinberg y la deriva genética - Cuestionario de evaluación | JoVE Lab Manual

Siga los procedimientos paso a paso de Hardy-Weinberg y la deriva genética en este video de protocolo estudiantil de 16 minutos. Parte de la colección Biology en JoVE Lab Manual.

Protocolo estudiantil de Hardy-Weinberg y la deriva genética en Biology - Más de 8.6K visualizaciones | JoVE Lab Manual

What is Natural Selection?

Natural selection is an evolutionary process in which individuals with survival-promoting traits reproduce at higher rates. These favorable traits become ...

Types of Selection

Natural selection influences the frequencies of particular alleles and phenotypes within populations in several different ways. Primarily, natural ...

Frequency-dependent Selection

When the fitness of a trait is influenced by how common it is (i.e., its frequency) relative to different traits within a population, this is referred to ...

Limits to Natural Selection

Organisms that are well-adapted to their environment are more likely to survive and reproduce. However, natural selection does not lead to perfectly ...

Natural Selection

Fitness
Widespread variation of phenotypes in natural populations provides the raw material for evolution, which is the change in the inherited traits of ...

Simulating Natural Selection
ExpandTo prepare for the lab, set out workstations for each student pair containing 6 white, 6 black, and 13 gray 12 inch ...

Simulating Natural Selection
ExpandTo begin, cut the white, black, and gray pipe cleaners into quarters, which should produce a total of 100 pieces that ...

Artificial Selection

Natural Selection and Adaptive Evolution
In natural settings, adaptive evolution takes place by natural selection, a process in which differences in ...

Observing Artificial Selection in Plants
ExpandTwo weeks before beginning the pollination experiments, collect a sufficient amount of small pots with a ...

Observing Artificial Selection in Plants 
ExpandTo begin the experiment, collect five two-week old grown plants from the generation one population that ...

What is Population Genetics?

A population is composed of members of the same species that simultaneously live and interact in the same area. When individuals in a population breed, ...

Hardy-Weinberg Principle

Diploid organisms have two alleles of each gene, one from each parent, in their somatic cells. Therefore, each individual contributes two alleles to the ...

Mutation, Gene Flow, and Genetic Drift

In a population that is not at Hardy-Weinberg equilibrium, the frequency of alleles changes over time. Therefore, any deviations from the five conditions ...

Genetic Drift

Natural selection&#x2014;probably the most well-known evolutionary mechanism&#x2014;increases the prevalence of traits that enhance survival and ...

Gene Flow

Gene flow is the transfer of genes among populations, resulting from either the dispersal of gametes or from the migration of individuals.

This ...

Evolutionary change is interesting and important to study, but changes in populations occur over long periods of time and in huge physical spaces and are ...


	Mathematical ModelingExpand
	
		
		Before beginning the mathematical modeling exercise make sure each computer has access to an either on or offline ...

Class Simulation
ExpandBegin by opening a new spreadsheet file. Following the Hardy-Weinberg equation where p is the frequency of a dominant allele A in a ...

Mechanisms
• Natural selection
• Mutation
• Genetic drift
• Gene flow (immigration, emigration)
• Sexual selection

Content elaboration: Natural selection is used to describe the process by which traits become more or less common in a population due to consistent environmental pressures upon the survival and reproduction of individuals with the trait. Mathematical reasoning is applied to solve problems (e.g., use Hardy-Weinberg principle to explain deviations in observed gene frequency patterns in a population compared to expected patterns based on the assumptions of the principle). Populations evolve over time. Evolution through natural selection is the consequence of the interactions of:
1. The potential for a population to increase its numbers; 
2. The genetic variability of offspring due to mutation and recombination of genes; 
3. A finite supply of the resources required for life; and 
4. The differential survival and reproduction of individuals based on phenotype(s). 
Mutations are described in the content elaboration for Heredity. Apply the knowledge of mutation and genetic drift to real-world examples. Biological evolution explains the natural origins for the diversity of life. Emphasis shifts from thinking in terms of selection of individuals with a particular trait to changing proportions of a trait in populations as a result of the mechanisms of natural selection, genetic drift, movement of genes into and out of populations and sexual selection.

Taxonomy

Taxonomy is the science of defining and naming groups of biological organisms based on shared characteristics. It uses a hierarchy of increasingly ...

Phylogeny

Phylogeny is concerned with the evolutionary diversification of organisms or groups of organisms. A group of organisms with a name is called a taxon ...

evolutionary-relationships-through-genome-comparisons

Evolutionary Relationships through Genome Comparisons

Genome comparison is one of the excellent ways to interpret the evolutionary relationships between organisms. The basic principle of genome comparison is ...

Genome Copying Errors

DNA replication is a well-evolved process that copies millions of base pairs with high fidelity during each cell division. Occasionally a wrong base or a ...

Phylogenetic Trees

Synteny and Evolution

John H. Renwick first coined the term &#8220;synteny&#8221; in 1971, which refers to the genes present on the same chromosomes, even if they are not ...

Multi-species Conserved Sequences

Next-generation sequencing technologies have created large genomic databases of a variety of animals and plants. Ever since the human genome project was ...

Gene Duplication and Divergence

The seminal work of Ohno in 1970 popularized the idea of gene duplication and divergence. DNA sequence comparison studies reveal that a large portion of ...

Exon Recombination

The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new ...

comparing-copy-number-variations-and-snps

Comparing Copy Number Variations and SNPs

Sequencing of the human genome has opened up several best-kept secrets of the genome. Scientists have identified thousands of genome variations that exist ...

Speciation
• Biological classification expanded to molecular evidence
• Variation of organisms within a species due to population genetics and gene frequency

Content elaboration: Biological classification expanded to molecular evidence
Classification systems are frameworks, developed by scientists, for describing the diversity of organisms; indicating the degree of relatedness among organisms. Recent molecular sequence data generally support earlier hypotheses regarding lineages of organisms based upon morphological comparisons. Both morphological and molecular comparisons can be used to describe patterns of biodiversity (cladograms present hypotheses to explain descent from a common ancestor with modification). The concept of descent from a common ancestor with modification provides a natural explanation for the diversity of life on Earth as partially represented in the fossil record and in the similarities of existing species. 
Variation of organisms within a species due to population genetics and gene frequency
Different phenotypes result from new combinations of existing genes or from mutations of genes in reproductive cells. At the high school level, the expectation is to combine grade 8 knowledge with an explanation of genes and the function of chromosomes. Natural selection works on the phenotype. Heritable characteristics influence how likely an organism is to survive and reproduce in a particular environment. When an environment changes, the survival value of inherited characteristics may change. This may or may not cause a change in species that inhabit the environment. Use real-world examples to illustrate natural selection, gene flow, sexual selection, and genetic drift.

Speciation

Genetic Drift Simulation and Hardy-Weinberg Lab Prep

Learning Objectives

¿Qué es el principio de Hardy-Weinberg y por qué es útil?

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