Name: sex-linked disorders and inheritance patterns
Uploaded: 2021-04-07T12:11:58.000Z
Duration: 1 min 43 s
Channel: JoVE

K12 Standards

Louisiana Student Standards for Science

High School

Life Sciences

heredity-inheritance-and-variation-of-traits

Heredity: Inheritance And Variation Of Traits

HS-LS3-2

Sex Linked Disorders

一些遗传性疾病 是由单个基因的突变引起的。
 当位于性别染色体上时， 这种疾病被认为与性别有关。
 根据基因所在的性别染色体 以及一个或两个拷贝是否是 正常功能所需， 这些疾病被认为是Y连锁， X连锁显性或X连锁隐性。
 首先，Y染色体不育等Y连锁疾病 是由位于Y染色体上的基因突变引起的， 只能从父亲遗传给儿子。
 其次，包括脆性X染色体综合症在内的 X连锁显性疾病 仅需要一个突变基因拷贝， 就会影响女性和男性， 不能从父亲传给儿子。
 最后，X连锁隐性遗传病 更常影响男性， 因为雌性需要两个突变基因拷贝。
 然而，未受影响的杂合女性可以成为携带者 并有50％的机会将其传递给儿子。
 例如，一种名为Duchenne Muscular Dystrophy 或DMD的X连锁隐性疾病 几乎会完全影响男孩。
 DMD由编码肌营养不良蛋白的基因突变引起， 肌营养不良蛋白参与骨骼肌 和心肌细胞的适当收缩和修复。
 这些突变可导致肌营养不良蛋白的结构 或功能改变， 肌肉细胞减弱并最终萎缩。

Colaco、Stacy 和 Deepak Modi。"人类 Y 染色体的遗传学及其与男性不育症的关系。"生殖生物学和内分泌学 16，第 1 期（2018 年）:14。[<a href="https://dx.doi.org/10.1186%2Fs12958-018-0330-5">来源</a>]

中村昌纪。"杜氏肌营养不良症的基于突变的治疗策略:从基因诊断到治疗。"个性化医学杂志 9，第 1 期（2019 年）:16。[<a href="https://dx.doi.org/10.3390%2Fjpm9010016">来源</a>]

性连锁疾病

像常染色体一样，性染色体含有正常身体功能所必需的各种基因。当这些基因之一的突变导致生物学缺陷时，该病症被认为是性别相关的。
Y染色体突变被称为“Y-连锁”，只影响男性，因为他们只携带该染色体的一个拷贝。相对较小的Y染色体突变可以影响男性的性功能和第二性征。Y染色体不育是一种影响精子产生的疾病，由Y染色体的无精子症因子（AZF）区域的缺失引起。一般来说，Y染色体连锁的疾病只会从父亲传给儿子；然而，由于受影响的男性通常不会在没有辅助生殖技术的情况下为孩子做父亲，因此Y染色体不育通常不会传给后代。
X连锁疾病可以是显性或隐性的。X连锁显性遗传病是X染色体突变的结果，这种突变可以影响男性或女性。然而，一些疾病，包括脆性X综合征，对男性的影响比女性严重，可能是因为男性没有第二个正常的X染色体拷贝。脆性X综合征的特点是广泛的发展问题，包括学习障碍。X-连锁低磷血症是另一种X-连锁显性疾病，表现为对维生素D有抵抗力的佝偻病。
要使隐性突变引起生物缺陷，染色体的两个拷贝都必须突变。因此，女性必须接受两条突变的X染色体才能显示X染色体连锁障碍。相反，如果男性的单个X染色体携带突变，则会受到影响。因此，男性更常受到X连锁隐性疾病的影响，包括色盲、杜氏肌营养不良和血友病。

与常染色体类似，性染色体也包含多种对机体正常功能至关重要的基因。当这些基因之一发生突变并导致生物学...

Education

教育

JoVE Core

Molecular Biology

分子生物学

Unit 2

第二单元

Mendelian Genetics

孟德尔遗传学

KEY TERMS AND CONCEPTS

关键术语与概念

性相关疾病

sex-linked disorders and inheritance patterns

Sex-linked disorders are genetic conditions that follow inheritance patterns tied to the sex chromosomes. These disorders help explain how certain traits can appear more often in one sex than the other.

The transcript focuses on examples of sex-linked disorders, including Y-linked infertility, Fragile X syndrome, and Duchenne muscular dystrophy. Y-linked infertility is passed through the Y chromosome, while Fragile X syndrome and Duchenne muscular dystrophy are associated with sex-linked inheritance on the X chromosome.

These examples show how the location of a gene on a sex chromosome affects who can inherit and express a disorder. Studying sex-linked disorders is an important part of Mendelian genetics because it connects chromosome inheritance with real genetic conditions.

Sex-Linked Disorders and Inheritance Patterns

sex-linked-disorders-inheritance-patterns

punnett squares

Predicting Traits with Punnett Squares

Punnett squares help students predict how traits may be passed from parents to offspring. They are a simple grid used in genetics to organize possible allele combinations. An allele is a version of a gene. The square compares the alleles each parent can give. By filling in the boxes, students can see possible genotypes, which are the genetic makeup of offspring. The results can also help connect those genotypes to traits that may appear in the next generation.

monohybrid crosses

Tracking One Trait in Monohybrid Crosses

Monohybrid crosses track how one trait is passed from parents to offspring. They are used to study inheritance when only a single characteristic is followed at a time. A monohybrid cross can compare the possible outcomes for a monogenic trait, which is a trait controlled by one gene. This approach helps show how one gene can shape different inherited forms of the same characteristic. The method also connects with Mendel's work on genetics. It is a useful way to predict patterns of inheritance...

dihybrid crosses

Predicting Two-Trait Genetic Crosses

Dihybrid crosses are used to predict how two traits can be passed from parents to offspring. A dihybrid cross tracks two genes at the same time, so it helps students see how different alleles can combine in a genetic pattern. This topic is closely tied to Mendelian genetics and independent assortment. Independent assortment means that allele pairs for different traits can separate into gametes independently of one another. When students work through a dihybrid cross, they can compare the...

trihybrid crosses

Forked Line Method for Trihybrid Crosses

Forked line method for trihybrid crosses helps predict the outcome of three-trait Mendelian crosses. A trihybrid cross studies three pairs of contrasting characteristics. It combines three separate monohybrid crosses. Common examples include plant height, seed shape, and seed color. In a typical trihybrid cross, the F1 plants are heterozygous for all three traits. They can produce eight different gametes. After self-fertilization, these gametes can lead to 64 genotype combinations in the F2...

law of independent assortment

Independent Chromosome Assortment in Meiosis

Independent chromosome assortment in meiosis explains how different gene pairs can be inherited independently. This idea is one of Mendel’s laws of inheritance and is often called the law of independent assortment. The pattern depends on how homologous chromosomes line up during meiosis I. Each chromosome pair orients independently of the others, so the maternal and paternal chromosomes can separate into different gametes in many combinations. This random separation helps create genetic...

chi-square analysis

Chi-Square Test in Genetics

The chi-square test in genetics helps compare expected and observed results. It is a statistical hypothesis test used to see whether a difference between an expected value and an observed value is significant. In genetics, it helps decide whether to accept or reject a hypothesis based on how far the observed data moves from the expected data. The test was developed by Pearson in 1990. The first step is to set up a null hypothesis. This hypothesis says there is no real difference between the...

pedigree analysis

Tracing Traits with Pedigree Charts

Pedigree analysis uses family trees, called pedigrees, to trace how traits and diseases pass from one generation to the next. A pedigree chart helps scientists and students see inheritance patterns clearly across relatives. The chart uses standard symbols to show family members and their relationships. It can reveal whether a trait is likely passed through dominant or recessive inheritance, and it can also help identify patterns linked to sex chromosomes. By studying a pedigree, it is...

multiple allele traits

Multiple Alleles in Trait Inheritance

Multiple alleles can shape how a trait is inherited in a population. A gene may have more than two allele forms, even though each person still carries only two alleles for that gene. These allele combinations can produce traits with more than two possible outcomes. The ABO blood group system is a common example of a multiple allele trait. It shows how different alleles can interact to determine an organism’s phenotype, or observable trait. Multiple allele traits help explain why inheritance...

incomplete dominance

Incomplete Dominance in Traits and Disease

Incomplete dominance is a pattern of inheritance where two alleles both affect a trait in a heterozygous organism. In this case, one allele is not fully dominant over the other. The result is a phenotype that looks like a blend or intermediate form. Gregor Mendel’s pea plant experiments helped explain the usual dominant and recessive pattern. He showed that each gene in a diploid cell has two alleles, one inherited from each parent. In his model, a dominant allele shows its effect with one or...

lethal alleles

When Genes Cause Embryonic Death

Lethal alleles can change inheritance patterns by causing death before birth. In mice, Lucien Cuénot studied the agouti gene, which helps control coat color through an agouti-signaling protein that affects melanin distribution in mammals. The wild-type allele produces a gray-brown coat, while the mutant allele produces a yellow coat. Cuénot also found that the yellow allele was linked to yellow mouse obesity syndrome. This syndrome is associated with early-onset obesity and tumors. When he...

polygenic traits

Traits Shaped by Many Genes

Polygenic traits are characteristics shaped by many genes acting together. This pattern is different from a single-gene trait, where one gene has a larger effect on the outcome. In polygenic inheritance, each gene adds a small contribution to the final trait. Height is a common example of a polygenic trait. Many genes influence human height, so the result can vary across a wide range. These small genetic effects combine to produce differences that are easy to see in a population. Polygenic...

background and environment affect phenotype

background-and-environment-affect-phenotype

How Genes and Environment Shape Traits

Genes and the environment work together to shape phenotype, or the visible traits of an organism. A phenotype can change because of genetic background, environmental conditions, or both. Factors such as temperature, oxygen availability, and mutagens can all influence how a trait appears. Horses show how one gene can affect coat color and how a modifier gene can change that result. The Extension gene controls pigment production in the coat. The wild-type genotype EE produces black pigment,...

x and y chromosomes

Sex Chromosomes in Human Inheritance

Sex chromosomes help determine biological sex in mammals, including humans. Humans have two sex chromosomes, X and Y. Each diploid cell has 22 pairs of autosomes and one pair of sex chromosomes. A female usually has two X chromosomes, while a male usually has one X chromosome and one Y chromosome. Egg and sperm cells carry only half the usual number of chromosomes. They contain 22 autosomes and one sex chromosome. Every egg has an X chromosome. Sperm cells can carry either an X or a Y...

the y chromosome determines maleness

Y Chromosome Structure and Male Traits

The Y chromosome is a sex chromosome that helps guide male development in humans and other vertebrates and mammals. Human males usually have one X chromosome and one Y chromosome, along with 22 pairs of autosomes. In these organisms, the presence or absence of the Y chromosome influences whether male traits develop. The Y chromosome evolved from an autosome about 300 million years ago, when two sex chromosomes began to diverge. Since then, it has lost most of its genes and become much smaller.

the ratio of x chromosome to autosomes

Drosophila Sex Determination by X:A Balance

In Drosophila, sex is determined by the balance between X chromosomes and autosomes, not by the X and Y chromosomes alone. The Y chromosome is active in these flies, but it does not set sex. Instead, it carries genes needed for sperm production in adult males. A normal male Drosophila has one X chromosome and two sets of autosomes. A normal female has two X chromosomes and two sets of autosomes. When this X:A ratio changes, flies can develop different sexual phenotypes, including metamales,...

x-linked traits

X-Linked Inheritance in Families

X-linked inheritance in families explains how traits linked to the X chromosome pass from parents to children. These traits are often tracked through family trees because the pattern can differ between males and females. A male has one X chromosome and one Y chromosome. A female has two X chromosomes. Because of this difference, a trait on the X chromosome can show up in a different way depending on the sex of the child. Family examples often include traits such as color blindness. Studying...

sex linked disorders

Sex-linked disorders are genetic conditions that follow inheritance patterns tied to the sex chromosomes. These disorders help explain how certain traits can appear more often in one sex than the other. The transcript focuses on examples of sex-linked disorders, including Y-linked infertility, Fragile X syndrome, and Duchenne muscular dystrophy. Y-linked infertility is passed through the Y chromosome, while Fragile X syndrome and Duchenne muscular dystrophy are associated with sex-linked...

dosage compensation

X-Chromosome Balance in Animals

X-chromosome balance in animals helps equalize gene expression between males and females. Sex can be determined by the number and type of sex chromosomes. In humans, females have two X chromosomes and males have one X and one Y chromosome. In C. elegans, one X chromosome is male, while two X chromosomes make a hermaphrodite. The X chromosome carries more than sex-related genes. It also includes genes involved in body functions such as brain development and the immune system. Because males and...

x-inactivation

X-Inactivation and Barr Bodies

X-inactivation is a process that reduces gene activity on one X chromosome. It helps balance gene expression in cells that have more than one X chromosome. A key result of this process is the formation of a Barr body, which is the inactive X chromosome seen in the nucleus. This topic also includes Xist, a gene linked to X-inactivation. Xist produces RNA that coats the X chromosome and helps turn it off. Together, Xist and the Barr body show how cells control X-linked genes during development...

blood types

Blood Types and Transfusion Matching

Human blood types help determine safe blood transfusion matching. Blood is classified by antigens on the surface of red blood cells and antibodies in the plasma. Correct blood typing matters because an unsafe match can affect transfusion success. The International Society of Blood Transfusion has identified 38 human blood types, and ABO, Rh, and MNS are among the most common. The ABO blood group depends on antigens made by genes on chromosome 9. Red blood cells carry a base glycoprotein called...

blood transfusion and agglutination

Matching Blood Types for Safe Transfusion

Blood transfusion is a medical treatment used to restore blood volume after major blood loss from an accident or a medical procedure. It works by taking blood from a suitable donor and giving it to a recipient. Safe transfusion depends on matching blood types and checking for immune compatibility. The history of blood transfusion began in the 17th century, when early experiments were done in animals. In 1818, James Blundell, a British doctor, performed the first successful human blood...

key terms and concepts

Learn how sex-linked disorders follow X-linked and Y-linked inheritance, with examples like Y-linked infertility, Fragile X syndrome, and Duchenne muscular dystrophy.

Sex-Linked Disorders and Inheritance Patterns | JoVE K12

molecular biology

JoVE Core 分子生物学通过清晰简洁的动画视频课程展示了细胞的分子过程。此外，在科学家在行动的视频中，这些概念的应用是通过现代实验室中的真实实验演示的。

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

9-12

Biology

Heredity

Genetic mechanisms and inheritance

Alabama Course of Study Science

Heredity: Inheritance and Variation of Traits

9-12.B.3.11.a

Texas Essential Knowledge and Skills

BIO.8

BIO.8.B

myJoVE Corporation

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The Tree of Life - Bacteria, Archaea, and Eukaryotes

Prokaryotic Cells

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Cytoplasm

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The Nucleus

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The DNA Helix

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The Nucleosome

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The Nucleosome Core Particle

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Nucleosome Remodeling

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Chromatin Packaging

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Karyotyping

Histone Modification

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Spreading of Chromatin Modifications

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Histone Variants at the Centromere

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Inheritance of Chromatin Structures

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Euchromatin

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Heterochromatin

chromatin-position-affects-gene-expression

Chromatin Position Affects Gene Expression

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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 ...

Pedigree Analysis

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

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

Formulate, refine, and evaluate questions to clarify relationships about the role of DNA and chromosomes in coding the instructions for characteristic traits passed from parents to offspring. Emphasis should be on traits including completely dominant, codominant, incompletely dominant, and sex-linked traits (e.g., pedigrees, karyotypes, genetic disorders, Punnett squares). Examples do not need to include dihybrid crosses.

HS-LS3-1

X and Y Chromosomes

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The Y Chromosome Determines Maleness

The Y chromosome is a sex chromosome&#160;found in several vertebrates and mammals, including humans. In addition to 22 pairs of autosomes, the human ...

The Ratio of X Chromosome to Autosomes

In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined ...

X-linked Traits

Dosage Compensation

In animals, gender is determined by the number and type of sex chromosome. For example, human females have two X chromosomes, and males have one X and one ...

X-inactivation

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 ...

Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors. Emphasis is on using data to support arguments for the way variation occurs. Claims should not include the phases of meiosis or the biochemical mechanisms of specific steps in the process.

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 ...

Apply concepts of statistics and probability to explain the variation and distribution of expressed traits in a population. Emphasis is on distribution and variation of traits in a population and the use of mathematics (e.g., calculations of frequencies in Punnett squares, graphical representations) to describe the distribution.

HS-LS3-3

Sex-Linked Disorders and Inheritance Patterns

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