Name: reading family traits in pedigrees
Uploaded: 2026-08-26T08:20:46.165Z
Duration: 2 min 21 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

NC K-12 Science Standard Course of Study

9-12

Biology

heredity-inheritance-and-variation-of-traits

Heredity- Inheritance and Variation of Traits

LS.Bio.7.2

Pedigree Analysis

- [Narrador] Para entender c&#xF3;mo los rasgos

o des&#xF3;rdenes son heredados en los humanos,

los cient&#xED;ficos analizan el &#xE1;rbol familiar

tambi&#xE9;n conocido como pedigr&#xED;.

En un pedigr&#xED; t&#xED;pico,
lo cuadrados son machos,

los c&#xED;rculos indican hembras

y una l&#xED;nea horizontal entre estas figuras

representa el emparejamiento.

Si esta uni&#xF3;n produce ni&#xF1;os,

se dibuja una l&#xED;nea perpendicular
debajo de los padres

hacia los hijos e hijas.

Esto va haciendo filas
debajo progresivamente

en el pedigr&#xED;

representando a las generaciones
subsecuentes en la familia.

Para quienes demuestren
un fenotipo de enfermedad,

como erupciones en la piel asociadas con

el d&#xE9;ficit de biotinidasa

en el que una persona no
tiene la enzima necesaria

para obtener vitamina B7,

las formas asociadas en
la genealog&#xED;a se sombrean.

Al concluir qu&#xE9; miembros
de la familia han sido

diagnosticados con d&#xE9;ficit de biotinidasa,

los investigadores pueden determinar

si la enfermedad resulta

de una mutaci&#xF3;n recesiva o
dominante de un solo gen,

situados en un autosoma
o cromosoma sexual.

Aqu&#xED; las hembras y machos son
afectados de la misma forma.

Los padres no afectados
tienen hijos con ese desorden

y no cada generaci&#xF3;n tiene
a un miembro de la familia

con la enfermedad, un patr&#xF3;n que sugiere

que el d&#xE9;ficit de biotinidasa
es un autosoma recesivo.

De modo importante el an&#xE1;lisis
de pedigr&#xED; no s&#xF3;lo elucida

patrones heredados,

sino que tambi&#xE9;n ayudan
a las parejas a entender

su riesgo de tener un ni&#xF1;o con el desorden

dado en su historia familiar.

Chial, Heidi. 2008. "Genética mendeliana: patrones de herencia y trastornos de un solo gen". Educación de la Naturaleza 1 (1): 63. [<a href="https://www.nature.com/scitable/topicpage/mendelian-genetics-patterns-of-inheritance-and-single-966" target="__blank">Fuente</a>]

Germain, Dominique P. 2006. "Aspectos generales de las enfermedades ligadas al cromosoma X". En Fabry Disease: Perspectives from 5 Years of FOS, editado por Atul Mehta, Michael Beck y Gere Sunder-Plassmann. Oxford: Oxford PharmaGenesis. [<a href="https://www.ncbi.nlm.nih.gov/books/NBK11593/" target="__blank">Fuente</a>]

análisis de pedigrí

<h4>Descripci&#xF3;n general</h4> Un pedigr&#xED; es un diagrama que muestra la historia de un rasgo en una familia. El an&#xE1;lisis de genealog&#xED;as puede revelar (1) si un rasgo es dominante o recesivo, (2) el tipo de cromosoma, autos&#xF3;mico o sexual, al que est&#xE1; vinculado un rasgo, (3) genotipos de miembros de la familia y (4) probabilidades de fenotipos en el futuro. generaciones. Para familias con antecedentes de enfermedades autos&#xF3;micas o ligadas al sexo, esta informaci&#xF3;n puede ser crucial para la planificaci&#xF3;n familiar. <h4>Los pedigr&#xED;es muestran historias familiares</h4> En diversas especies de plantas y animales, los cient&#xED;ficos estudian la herencia de fenotipos o rasgos mediante experimentos de apareamiento cuidadosamente controlados llamados cruces. Por ejemplo, los cruces monoh&#xED;bridos pueden establecer un rasgo de dominancia o recesividad, y los cruces de prueba pueden determinar el genotipo (homocigoto o heterocigoto) de un organismo que exhibe un fenotipo dominante conocido. Los seres humanos, sin embargo, no pueden ser contrariados ni desde el punto de vista &#xE9;tico ni factible. Por lo tanto, los investigadores analizan genealog&#xED;as o &#xE1;rboles geneal&#xF3;gicos para comprender c&#xF3;mo se heredan los rasgos y enfermedades humanos. Los pedigr&#xED;es muestran la historia familiar de un rasgo a trav&#xE9;s de generaciones y miembros de la familia. Utilizando los mismos principios que se aplican a los cruces para analizar eventos reproductivos que ya han ocurrido, se puede inferir informaci&#xF3;n sobre la heredabilidad de los rasgos. <h4>Las filas de un pedigr&#xED; representan generaciones de una familia</h4> En un pedigr&#xED; t&#xED;pico, los cuadrados representan machos y los c&#xED;rculos representan hembras. Los cuadrados o c&#xED;rculos sombreados indican la presencia de un rasgo de inter&#xE9;s. Las filas son generaciones, a veces etiquetadas con n&#xFA;meros romanos. La generaci&#xF3;n m&#xE1;s antigua comprende la fila superior, y cada generaci&#xF3;n posterior est&#xE1; en filas separadas. Dentro de cada generaci&#xF3;n, o fila, los miembros de la familia pueden etiquetarse num&#xE9;ricamente de izquierda a derecha y hacer referencia a ellos por su generaci&#xF3;n y posici&#xF3;n. Por ejemplo, el segundo individuo de la primera generaci&#xF3;n es I-2. Una l&#xED;nea horizontal que conecta a dos padres se llama l&#xED;nea matrimonial, aunque el matrimonio no necesariamente est&#xE1; involucrado. Una l&#xED;nea vertical de descendencia que se extiende hacia abajo desde una l&#xED;nea matrimonial se conecta a una l&#xED;nea horizontal de hermanos. Los individuos conectados a la l&#xED;nea de descendencia a trav&#xE9;s de la l&#xED;nea de hermanos son descendientes. Las personas que no est&#xE1;n directamente relacionadas con la l&#xED;nea de hermanos ingresaron a la familia a trav&#xE9;s de l&#xED;neas matrimoniales y no son descendientes biol&#xF3;gicos de la generaci&#xF3;n anterior. <h4>Los pedigr&#xED;es revelan informaci&#xF3;n sobre la herencia de rasgos y enfermedades</h4> Los rasgos dominantes se distribuyen de forma diferente a los recesivos. La herencia tambi&#xE9;n es distinta para los rasgos determinados por genes en los cromosomas sexuales en comparaci&#xF3;n con los rasgos vinculados a los autosomas (cromosomas no sexuales). Al examinar la presencia y ausencia de un rasgo a lo largo de la historia de una familia, el an&#xE1;lisis geneal&#xF3;gico puede proporcionar informaci&#xF3;n sobre la herencia del rasgo. Aunque muchas enfermedades est&#xE1;n influenciadas por m&#xFA;ltiples genes, varias muestran patrones de herencia mendeliana. Para estas condiciones, los pedigr&#xED;es pueden dar pistas importantes sobre el riesgo de herencia y propagaci&#xF3;n de enfermedades. Los rasgos causados por genes en los autosomas y que requieren dos copias de alelos para influir en un fenotipo son autos&#xF3;micos recesivos. Varios trastornos son autos&#xF3;micos recesivos, incluida la fibrosis qu&#xED;stica, la enfermedad de Tay-Sachs y la enfermedad de la orina con jarabe de arce. La mayor&#xED;a de las personas con estas enfermedades tienen padres heterocigotos que no padecen la afecci&#xF3;n pero que portan un alelo causal. Estos portadores pueden, sin saberlo, transmitir la enfermedad a sus hijos, lo que explica en parte por qu&#xE9; las enfermedades autos&#xF3;micas recesivas son m&#xE1;s comunes que sus contrapartes dominantes. La comparaci&#xF3;n de generaciones en un pedigr&#xED; puede revelar si un rasgo autos&#xF3;mico es dominante o recesivo. Ninguno de los padres tiene el rasgo, pero uno de los hijos lo hereda. Por tanto, debe ser recesivo. Las pecas y el polidactilismo (dedos adicionales en manos o pies) son rasgos autos&#xF3;micos dominantes en los humanos, que requieren solo una copia del alelo determinante para influir en el fenotipo. Las enfermedades autos&#xF3;micas dominantes, como la enfermedad de Huntington, afectan a aproximadamente el 50% de la descendencia con un progenitor afectado. Muchas de estas enfermedades no causan s&#xED;ntomas hasta una etapa m&#xE1;s avanzada de la vida, despu&#xE9;s de la edad reproductiva. Los ni&#xF1;os pueden heredar estas enfermedades de padres afectados sin saberlo, lo que destaca la importancia de analizar los antecedentes familiares. Aunque ambos padres exhiben el rasgo, uno de sus hijos no. Dado que un cruce entre dos padres recesivos produce consistentemente un fenotipo recesivo, este rasgo debe ser dominante. <h4>Los rasgos pueden ser autos&#xF3;micos o ligados al sexo</h4> Adem&#xE1;s de 44 autosomas, los humanos tenemos dos cromosomas sexuales, que son hom&#xF3;logos en las mujeres (XX), pero no hom&#xF3;logos en los hombres (XY). Los rasgos determinados por los cromosomas sexuales est&#xE1;n ligados al sexo. La mayor&#xED;a de los rasgos ligados al sexo en los seres humanos son recesivos ligados al cromosoma X. S&#xF3;lo los hombres pueden heredar rasgos ligados al Y porque las mujeres carecen de un cromosoma Y. Adem&#xE1;s, el cromosoma X contiene entre 800 y 900 genes codificadores de prote&#xED;nas, en comparaci&#xF3;n con los 70 a 80 del cromosoma Y. Los rasgos ligados al cromosoma X incluyen hemofilia, distrofia muscular y daltonismo rojo-verde. Dado que los hombres tienen s&#xF3;lo un cromosoma X, son hemicigotos (en lugar de homocigotos o heterocigotos) para un rasgo ligado al cromosoma X. Los hombres son m&#xE1;s susceptibles a los rasgos recesivos ligados al cromosoma X que las mujeres porque no tienen un segundo alelo que pueda enmascarar potencialmente un alelo recesivo causal.

Análisis de pedigrí

Overview

A pedigree is a diagram displaying a family&#x2019;s history of a trait. Analyzing pedigrees can reveal (1) whether a trait is dominant or ...

https://cloudfront.jove.com/files/ftp_upload/10775/10775_article_thumb_10775.jpg

Education

Educación

JoVE Core

Biología

Genetics

Genética

Classical and Modern Genetics

Genética Clásica y Moderna

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

reading family traits in pedigrees

Pedigrees are family trees used to track how a trait passes through generations. They help scientists and students see whether a trait is dominant or recessive, whether it is autosomal or sex-linked, what genotypes family members may have, and what phenotypes may appear in future generations. For families with a history of inherited disease, this information can be important for family planning.

In plants and animals, inheritance is often studied with crosses. Monohybrid crosses can show whether a trait is dominant or recessive, and test crosses can help identify whether an organism with a dominant trait is homozygous or heterozygous. Humans cannot be crossed for ethical or practical reasons, so pedigrees are used instead. A pedigree records reproductive events that have already happened and lets scientists infer how a trait is inherited.

Pedigree symbols follow a clear pattern. Squares stand for males, and circles stand for females. Shaded symbols show the trait of interest. The top row is the oldest generation, and each lower row is a later generation. Family members in a generation may also be numbered from left to right, such as I-2. A line between two adults marks a parent pair, and a line downward connects them to their children through a sibling line.

Looking across generations can reveal inheritance patterns. If neither parent shows a trait but one child does, the trait is likely recessive. Traits caused by genes on autosomes and needing two allele copies are called autosomal recessive. Examples include cystic fibrosis, Tay-Sachs disease, and maple syrup urine disease. In many cases, the parents are heterozygous carriers who do not show the condition but can pass the allele to their children.

A pedigree can also point to dominant traits. Freckles and polydactylism, or extra fingers or toes, are autosomal dominant traits. Only one copy of the allele is needed to affect phenotype. Huntington’s disease is another autosomal dominant example, and about 50% of offspring may be affected when one parent has the trait. Some dominant diseases do not show symptoms until later in life, which is why family history can matter even when parents seem healthy. If both parents show the trait but one child does not, the trait is likely dominant because two recessive parents would produce only the recessive phenotype.

Pedigrees also help identify sex-linked traits. Humans have 44 autosomes and two sex chromosomes. Females are XX, and males are XY, so the sex chromosomes are homologous in females but not in males. Traits on sex chromosomes are sex-linked. Most sex-linked traits in humans are X-linked recessive. Examples include hemophilia, muscular dystrophy, and red-green color blindness. Males have only one X chromosome, so they are hemizygous for X-linked traits and are more likely to show a recessive X-linked allele because there is no second copy to mask it. Y-linked traits can be inherited only by males, since females do not have a Y chromosome.

Reading Family Traits in Pedigrees

genetic lingo

Genotype, Phenotype, and Inheritance

Genotype, phenotype, and inheritance help explain how traits and disease risk are passed from parents to offspring. In diploid organisms, including humans, most other animals, and many plants, somatic cells carry a duplicate set of chromosomes. These chromosome pairs are homologous, with similar length, centromere position, and gene locations. Diploid organisms inherit two versions of each gene, one from each parent. These versions are called alleles, and they sit at the same relative locus,...

punnett squares

Punnett Squares for Predicting Traits

Punnett squares help predict which traits offspring may inherit from two parents. They show possible genotypes, which are pairs of alleles, and can also show the chance of a phenotype, or visible trait, when the inheritance pattern is known. These grids work best for traits controlled by a single gene locus and passed on independently during meiosis. Punnett squares were developed in the early 1900s by Reginald Punnett. His work came after Gregor Mendel’s pea plant experiments revealed the...

monohybrid crosses

Mendel’s Pea Plant Inheritance Ratios

Gregor Mendel used pea plants to study how traits are passed from parents to offspring. His breeding experiments in the 1850s and 1860s showed that inheritance follows clear patterns. He crossed true-breeding plants that differed in one trait and found that dominant traits can hide recessive traits. Mendel focused on seven pea plant traits, and each trait had two forms controlled by a single gene locus. He noticed that true-breeding plants always produced offspring with the same phenotype, or...

dihybrid crosses

Mendel's Law of Independent Assortment

Mendel’s law of independent assortment explains how two traits can be inherited separately. Gregor Mendel tested this idea with pea plants that differed in two characteristics, such as pea color and pea shape. He used true-breeding parents that were homozygous for both traits but showed different phenotypes. In one example, Mendel crossed round, yellow peas with wrinkled, green peas. The parental generation had RRYY and rryy genotypes. Their first-generation offspring were all dihybrids,...

law of segregation

Mendel’s Pea Cross Ratios

Mendel’s pea plant crosses show how traits can disappear in one generation and return in the next. When he crossed plants, one parental trait sometimes seemed to vanish in the F1 generation and reappear in the F2 generation. Mendel used this pattern to explain why some traits are dominant and others are recessive. He proposed that traits are controlled by alleles, which are different versions of a gene. An organism inherits two copies of each gene, one from each parent. In his model, a...

law of independent assortment

Mendel’s Dihybrid Cross and Trait Ratios

Mendel’s dihybrid cross shows how two traits are inherited at the same time. A dihybrid cross is a cross in which both parents are homozygous for two distinct traits, and the F1 generation is heterozygous for both traits. Mendel used pea plants with round yellow peas and wrinkled green peas as an example. One parent had genotype YYRR, and the other had genotype yyrr. In the F1 generation, every plant showed the dominant traits, so the plants were YyRr and had yellow, round peas. The F2...

test cross

Using Test Crosses to Identify Genotypes

Test crosses are used to identify the genotype of an organism with a dominant trait. A genotype is the pair of alleles inherited for a gene, and alleles are different forms of the same gene. In diploid organisms, including humans, each gene usually has two alleles, one from each parent. An allele is recessive when its effect is hidden by another allele at the same gene location. Pea plants provide a clear example with flower color. White flowers are recessive, because one copy of the purple...

probability laws

Inheritance Risk with Sum and Product Rules

Inheritance risk can be calculated with the sum rule and the product rule. The sum rule applies to mutually exclusive events, or events that cannot happen at the same time. The product rule applies to independent events, or events that do not affect one another. These rules describe theoretical probability, which is the chance of an event before it happens. Empirical probability is different because it is based on events that have already occurred. These probability rules are useful in...

pedigree analysis

Pedigrees are family trees used to track how a trait passes through generations. They help scientists and students see whether a trait is dominant or recessive, whether it is autosomal or sex-linked, what genotypes family members may have, and what phenotypes may appear in future generations. For families with a history of inherited disease, this information can be important for family planning. In plants and animals, inheritance is often studied with crosses. Monohybrid crosses can show...

multiple allele traits

Blood Type and Allele Interactions

Multiple alleles can shape traits through blood type, sickle cell anemia, incomplete dominance, and codominance. Multiple allelism means a gene has three or more allelic forms. Diploid organisms, including humans, usually carry only two alleles for each gene, but many human genes exist in multiple forms in the population. Human blood type is a clear example of multiple allelism. The blood type gene has three alleles: I A , I B , and i. These alleles help determine which blood type a person has...

epistasis

Gene Masking in Rabbit Fur Color

Epistasis describes how one gene can mask or change the effect of another gene. In high school genetics, this helps explain why many traits do not follow a simple single-gene pattern. Instead, alleles at different locations can work together to shape the final phenotype. Mendel studied seven unrelated pea traits, but most traits involve multiple gene interactions. Epistasis often happens when one gene interferes with the expression of another gene. It can also occur when genes are part of the...

polygenic traits

Polygenic Traits in Human Height

Polygenic traits are traits controlled by more than one gene. Human height is a clear example of this kind of inheritance. Because many genes work together, the final trait can vary a lot from person to person. Researchers have found hundreds of loci, or gene locations, that influence height. There are likely many more that have not yet been identified. Many of these genes affect cartilage in the growth plates of the long bones in the arms and legs, either directly or indirectly. Height is...

pleiotropy

SOX10 and Multiple Traits in Pleiotropy

Pleiotropy is when one gene affects more than one trait. The SOX10 gene is a clear example because it can influence pigmentation, hearing, and intestinal movement. These traits may seem unrelated, but they can all be linked to the same gene change. In humans, a deleted region in SOX10 can cause Waardenburg Syndrome Type 4, or WS4. WS4 is an autosomal recessive disorder, which means a person usually inherits two altered copies of the gene. Common signs include a white forelock,...

nature and nurture

Genes and Environment Shape Height

Genes and environment both shape human height and other traits. Genes are the inherited instructions we get from our parents. Environment includes factors such as diet, stress, and social conditions. Many phenotypes, or observable traits, reflect both influences. Some also show up later in life, including cancer and other diseases. Height is a clear example of this interaction. Scientists estimate that 70-90% of height variation comes from genetic differences among people. The remaining 10-30%...

chromosomal theory of inheritance

How Genes Map to Chromosomes

Genes map to chromosomes, and this idea explains how Mendel’s inheritance patterns work. Gregor Mendel published his pea plant breeding results in 1866. He showed that physical traits follow predictable patterns. At the time, scientists did not yet know that genes existed. Mendel used the word "factors" for the hereditary units he studied. The details behind Mendel’s laws of segregation and independent assortment were still unknown for many years. In the late 1800s, better microscopes and...

non-nuclear inheritance

Maternal DNA in Mitochondria and Chloroplasts

Maternal DNA in mitochondria and chloroplasts explains how some genes are inherited outside the nucleus. Most DNA is in the nucleus, but mitochondria and chloroplasts in the cell cytoplasm also carry their own DNA and can copy it independently of nuclear DNA. Mitochondria are found in both plant and animal cells. They are called the powerhouses of eukaryotic cells because they break down glucose to make energy for cellular activity. Mitochondrial DNA has about 37 genes, and many help with...

x-linked traits

X-Linked Inheritance in Families

X-linked inheritance explains how traits on the X chromosome are passed through families. In most mammalian species, females have two X sex chromosomes, while males have one X and one Y. A mutation on one X chromosome may be masked in females by a normal allele on the other X. In males, that same mutation is more likely to show because there is no second normal X to balance it. Traits caused by changes on the X chromosome are called X-linked traits. Color blindness is a well-studied example.

sex-linked disorders

X- and Y-Linked Disorder Patterns

X- and Y-linked disorders come from mutations in genes on the sex chromosomes. These genes, like those on autosomes, are needed for normal body function. When a mutation causes a biological problem, the condition is called sex-linked. Y-linked disorders come from changes in the Y chromosome. They affect only males, because only males carry a Y chromosome. Mutations in this small chromosome can affect male sexual function and secondary sex characteristics. One example is Y-chromosome...

x-inactivation

Barr Bodies and X-Chromosome Balance

Barr bodies and X-chromosome balance help explain how female mammalian cells control gene activity from the X chromosome. The human X chromosome carries far more genes than the Y chromosome. Because males usually have one X chromosome and females have two, females would make twice as many of some proteins without a control system. To prevent that imbalance, female mammalian cells inactivate nearly all the genes on one X chromosome during early embryonic development. The inactive X condenses...

key terms and concepts

Learn how pedigree charts reveal dominant, recessive, autosomal, and sex-linked inheritance, plus carrier status and future disease risk in families.

Reading Family Traits in Pedigrees | JoVE K12

JoVE Core series brings biology to life through over 300 concise and easy-to-understand animated video lessons that explain key concepts in biology, plus more than 150 scientist-in-action videos that show actual research experiments conducted in today’s laboratories.

biology

JoVE Core Biología da vida a la biología a través de una serie con más de 300 lecciones de vídeo animadas, concisas y fáciles de entender, que explican conceptos clave de la biología, incluyendo también más de 150 vídeos de científicos en acción, que muestran experimentos reales realizados en laboratorios actuales de investigación.

Tennessee Academic Standards

High School

Heredity

BIO1.LS3.3

Biological Change: Unity and Diversity

BIO1.LS4.1

Virginia  Standards of Learning

HIgh School

Life Science

LS.10

LS.10.c

Minnesota Academic Standards in Science

2.1.1 9L.2.1.1.1

new-jersey-student-learning-standards-for-science

New Jersey Student Learning Standards for Science

Heredity: Inheritance and Variation of Traits

HS-LS3-3

Next Generation Science Standards

HS-LS3-1

HS-LS4-3

new-york-state-science-learning-standards

New York State Science Learning Standards

Inheritance and Variation of Traits

HS-LS3-1.

Florida Department of Education

SC.912.L.16

SC.912.L.16.1

What is Meiosis?

Meiosis is the process by which diploid cells divide to produce haploid daughter cells. In humans, each diploid cell contains 46 chromosomes, half from ...

Meiosis I

Meiosis II

Meiosis vs. Mitosis

Crossing Over

Crossing over is the exchange of genetic information between homologous chromosomes during prophase I of meiosis I. Genetic recombination gives rise to ...

Nondisjunction

Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate correctly and move to the opposite poles of the cells. This ...

Spermatogenesis

Spermatogenesis is the process by which haploid sperm cells are produced in the male testes. It starts with stem cells located close to the outer rim of ...

Oogenesis

In human women, oogenesis produces one mature egg cell or ovum for every precursor cell that enters meiosis. This process differs in two unique ways from ...

Fertilization

During fertilization, an egg and sperm cell fuse to create a new diploid structure. In humans, the process occurs once the egg has been released from the ...

Cleavage and Blastulation

After a large-single-celled zygote is produced via fertilization, the process of cleavage occurs while zygotes travel through the uterine tube. Cleavage ...

Gastrulation

Gastrulation establishes the three primary tissues of an embryo: the ectoderm, mesoderm, and endoderm. This developmental process relies on a series of ...

Neurulation

Neurulation is the embryological process which forms the precursors of the central nervous system and occurs after gastrulation has established the three ...

Cell Migration

Cell migration, the process by which cells move from one location to another, is essential for the proper development and viability of organisms ...

Determination

During embryogenesis, cells become progressively committed to different fates through a two-step process: specification followed by determination. ...

Use models to explain how DNA is passed from parents to offspring through the processes of meiosis and fertilization in sexual reproduction.

LS.Bio.6.1

Mutations

Mutations are changes in the sequence of DNA. These changes can occur spontaneously or they can be induced by exposure to environmental factors. Mutations ...

genome-size-and-the-evolution-of-new-genes

Genome Size and the Evolution of New Genes

types-of-genetic-transfer-between-organisms

Types of Genetic Transfer Between Organisms

Base-pairing and DNA Repair

The DNA Replication Fork

Lagging Strand Synthesis

The Replisome

Proofreading

Synthesis of new DNA molecules is carried out by the enzyme DNA polymerase, which adds nucleotides on the daughter strand complementary to the template ...

Replication in Prokaryotes

DNA replication has three main steps: initiation, elongation, and termination. Replication in prokaryotes begins when initiator proteins bind to the ...

Replication in Eukaryotes

In eukaryotic cells, DNA replication is highly conserved and tightly regulated. Multiple linear chromosomes must be duplicated with high fidelity before ...

Overview of DNA Repair

Base Excision Repair

Nucleotide Excision Repair

DNA Distortion and Damage
Cells are regularly exposed to mutagens&#8212;factors in the environment that can damage DNA and generate mutations. UV ...

Mismatch Repair

Organisms are capable of detecting and fixing nucleotide mismatches that occur during DNA replication. This sophisticated process requires identifying the ...

Fixing Double-strand Breaks

Homologous Recombination

Gene Conversion

Restarting Stalled Replication Forks

Construct an explanation to summarize how inheritable genetic variations may result from: new genetic combinations in meiosis, mutations during replication, or mutations caused by environmental factors.

LS.Bio.6.2

An Overview of Genetic Analysis

An organism&#8217;s physical traits, or phenotype, are a product of its genotype, which is the combination of alleles (gene variants) inherited from its ...

Genetic Crosses

To dissect genetic processes or create organisms with novel suites of traits, scientists can perform genetic crosses, or the purposeful mating of two ...

Punnett Squares

Monohybrid Crosses

Dihybrid Crosses

Trihybrid Crosses

Trihybrid Crosses
Some of Mendel&#8217;s crosses examined three pairs of contrasting characteristics. Such a cross is called a trihybrid cross. A ...

Law of Independent Assortment

Chi-square Analysis

The chi-square test is a statistical hypothesis test. It is used to check whether there is a significant difference between an expected value and an ...

Multiple Allele Traits

Incomplete Dominance

Gregor Mendel&#39;s work (1822 - 1884) was primarily focused on pea plants. Through his initial experiments, he determined that every gene in a diploid ...

Lethal Alleles

Agouti: A Lethal Allele
Lucien Cu&#233;not discovered lethal alleles in 1905 while studying the inheritance of coat color in mice. The agouti gene is ...

Polygenic Traits

background-and-environment-affect-phenotype

Background and Environment Affect Phenotype

Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as ...

Use mathematics and computational thinking to predict the variation and distribution of expressed traits based on: Mendelian inheritance, co-dominance, incomplete dominance, multiple alleles, and sex-linked inheritance.

LS.Bio.7.1

Probability Laws

Overview

The probability of inheriting a trait can be calculated using the sum and product rules. The sum rule is used to calculate the probability of ...

The Concept of Multiple Allelism

Multiple allelism describes genes that exist in three or more allelic forms. Although diploid organisms, like humans, ...

Analyze and interpret data to explain how polygenic traits result in a wide range of phenotypes.

Understand genetic mechanisms for variation.

Reading Family Traits in Pedigrees

Description

Transcript

Tags

More videos by Standards