Name: y chromosome structure and male traits
Uploaded: 2021-04-07T12:11:58.000Z
Duration: 2 min 19 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

The Y Chromosome Determines Maleness

Hay dos cromosomas sexuales en los seres humanos: X e Y.
El cromosoma Y determina el sexo masculino y es el cromosoma más pequeño del genoma humano.
Hay tres regiones en el cromosoma Y: la porción pseudoautosómica, que a su vez se divide en dos regiones: PAR1 y PAR2, la región heterocromática y la región eucromática.
El gen S-R-Y se encuentra en la región eucromática del cromosoma Y. Desempeña un papel vital en el desarrollo de los fetos masculinos.
Cuando un óvulo portador de un cromosoma X se fusiona con un espermatozoide portador de un cromosoma Y, forma un cigoto.
Luego, el cigoto se divide continuamente para formar un embrión. En esta etapa, los embriones masculinos y femeninos se desarrollan a lo largo de la misma vía y son fisiológicamente idénticos.
Durante las primeras etapas del desarrollo, el embrión tiene dos órganos precursores: el conducto de Wolff y el conducto mülleriano.
El conducto de Wolff puede diferenciarse en estructuras genitales masculinas y el conducto mülleriano puede diferenciarse en estructuras genitales femeninas.
En las semanas posteriores a la fertilización, el gen S-R-Y presente en el cromosoma Y se transcribe y luego se traduce en la proteína S-R-Y. La proteína S-R-Y inicia el desarrollo de los testículos en el feto.
 La proteína S-R-Y actúa como un factor transcripcional y se une a sitios específicos en el ADN, activando así la vía de formación de los testículos.
Luego, las gónadas comienzan a secretar varias hormonas, incluida la hormona anti-mulleriana y la testosterona.
La hormona antimulleriana inhibe el desarrollo del conducto mülleriano.
La testosterona, por otro lado, inicia el desarrollo del conducto de Wolff en conductos deferentes, conductos eyaculatorios y vesículas seminales.
Si esta vía se interrumpe y las gónadas no pueden secretar testosterona y hormona anti-mülleriana, el conducto mülleriano se convierte en órganos reproductivos femeninos, incluso si el feto es genotípicamente XY.

<ol>
	<li>Willard, Huntington F. "Cuentos del cromosoma Y". Nature 423, no. 6942 (2003): 811-813.</li>
	<li>Ginalski, Krzysztof, Leszek Rychlewski, David Baker y Nick V. Grishin. "Predicción de la estructura de la proteína para la región específica masculina del cromosoma Y humano". Actas de la Academia Nacional de Ciencias 101, no. 8 (2004): 2305-2310.</li>
	<li>Noordam, Michiel J. y Sjoerd Repping. "El cromosoma Y humano: un cromosoma masculino". Current opinion in genetics & development 16, no. 3 (2006): 225-232.</li>
</ol>

el cromosoma y determina la masculinidad

El cromosoma Y es un cromosoma sexual que se encuentra en varios vertebrados y mamíferos, incluidos los humanos. Además de 22 pares de autosomas, los varones humanos tienen un cromosoma X y un cromosoma Y. En estos organismos, la presencia o ausencia del cromosoma Y determina el desarrollo de rasgos masculinos.

Evolución

Hace unos 300 millones de años, los dos cromosomas sexuales se separaron de dos cromosomas autosómicos idénticos. Con el tiempo, el cromosoma Y ha perdido la mayoría de sus genes y ha disminuido de tamaño. Hoy en día, sólo una pequeña parte del cromosoma Y comparte similitud de secuencia con el cromosoma X. Un gran estudio científico sobre los cromosomas Y en ocho mamíferos, incluidos monos, ratones, ratas, toros, zarigüeyas, chimpancés y humanos, mostró 18 regiones muy similares en los cromosomas Y. El hecho de que estas regiones se conserven en todos estos mamíferos, a pesar de perder una gran parte de los cromosomas Y durante la evolución, muestra que los genes de los cromosomas Y son vitales para la supervivencia de estos mamíferos.

Estructura

El cromosoma Y de los mamíferos tiene tres regiones principales. Las regiones pseudoautosómicas del cromosoma Y comparten homología con el cromosoma X y pueden sufrir recombinación meiótica. Por tanto, los genes presentes en las regiones pseudoautosómicas se heredan de forma autosómica y no ligada al sexo. La segunda región es una región de eucromatina designada como región del cromosoma Y específica del hombre o MSY. Tiene una longitud de 23 Mb y tiene pocos genes codificadores de proteínas, como el gen SRY, un regulador maestro de la masculinidad y el gen ZFY necesario para la espermatogénesis. La tercera región es una región de heterocromatina que contiene varias secuencias repetitivas.

Mutaciones y sus efectos.

Las deleciones en la región MSY del cromosoma Y afectan el desarrollo de los espermatozoides y causan esterilidad masculina. Por ejemplo, las deleciones en el gen AZF en el brazo largo del cromosoma Y provocan una afección llamada azoospermia, en la que no se encuentran espermatozoides en la eyaculación masculina. Además, las deleciones en regiones específicas de RMS se asocian con tumores de células germinales testiculares (TGCT).

El cromosoma Y determina la masculinidad

El cromosoma Y es un cromosoma sexual que se encuentra en varios vertebrados y mamíferos, incluidos los humanos. Además de 22 pares de autosomas, el humano ...

Education

Educación

JoVE Core

Molecular Biology

Biología Molecular

Unit 2

Unidad 2

Mendelian Genetics

Genética mendeliana

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

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. Only a small region still shares sequence similarity with the X chromosome. A large study of Y chromosomes in eight mammals, including monkeys, mice, rats, bulls, opossums, chimpanzees, and humans, found 18 highly similar regions. Their long-term retention suggests that Y-linked genes remain important for mammalian survival.

The mammalian Y chromosome has three main regions. The pseudoautosomal regions match parts of the X chromosome and can undergo meiotic recombination, which means they can be inherited more like autosomes than sex-linked genes. The second region is the male-specific Y chromosome region, or MSY. It is a euchromatin region about 23 Mb long and contains few protein-coding genes, including SRY, a master regulator of maleness, and ZFY, which is required for spermatogenesis. The third region is heterochromatin, which contains many repetitive sequences.

Changes in the MSY region can have major effects on reproduction. Deletions in this region can disrupt sperm development and lead to male sterility. For example, deletions in the AZF gene on the long arm of the Y chromosome can cause azoospermia, a condition in which spermatozoa are not found in the male ejaculate. Deletions in specific MSY regions are also linked to testicular germ cell tumors, or TGCTs.

Y Chromosome Structure and Male Traits

punnett squares

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the y chromosome determines maleness

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

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key terms and concepts

Explore how the Y chromosome evolved, how its three regions differ, and how MSY deletions can affect sperm development and male fertility.

Y Chromosome Structure and Male Traits | JoVE K12

molecular biology

JoVE Core Biología Molecular presenta los procesos moleculares de la célula a través de lecciones claras y concisas de animaciones audiovisuales. Además, en los vídeos de científicos en acción, se muestran aplicaciones de estos conceptos mediante experimentos reales en laboratorios especializados.

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Ohio’s Learning Standards and Model Curriculum

9-12

Biology

Heredity

Genetic mechanisms and inheritance

Tennessee Academic Standards

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Links Among Engineering, Technology, Science, and Society

BIO1.ETS2.2

Alabama Course of Study Science

Heredity: Inheritance and Variation of Traits

9-12.B.3.11.a

Next Generation Science Standards

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HS-LS3-1

Texas Essential Knowledge and Skills

BIO.8

BIO.8.B

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New York State Science Learning Standards

Inheritance and Variation of Traits

HS-LS3-1.

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Lethal Alleles

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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.

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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.

Y Chromosome Structure and Male Traits

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