Unidad de gen tica humana
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Unidad de Genética Humana. ADN (DNA) : Es el Material de Herencia de los Organismos. Es la molécula de ácido desoxirribonucleíco Estructura del DNA : Modelo propuesto por Watson, Crick y Wilkins. (1953). Consiste de una hélice doble de Nucleótidos. Fig. 16-1b, p. 348.

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Unidad de Genética Humana

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Unidad de Genética Humana

  • ADN (DNA) : Es el Material de Herencia de los Organismos.

  • Es la molécula de ácido desoxirribonucleíco

  • Estructura del DNA : Modelo propuesto por

    Watson, Crick y Wilkins. (1953).

  • Consiste de una hélice doble de Nucleótidos.


Fig. 16-1b, p. 348


Cromosomas


Composición del DNA

  • Composición del Nucleótido:

    • Azúcar desoxiribosa

    • 4 Bases Nitrogenadas:

      • Purinas: Adenina (A) y Guanina (G)

      • Pirimidinas: Citosina (C) y Timina (T)

    • Gruposfosfatos ( PO4)


Table 12-1, p. 263


Fig. 12-3, p. 264


Thymine

Nucleotide

Adenine

Cytosine

Phosphate group

Guanine

Phosphodiester linkage

Deoxyribose (sugar)

Fig. 12-3, p. 264


Fig. 12-5, p. 266


Adenine

Thymine

Deoxyribose

Deoxyribose

Guanine

Cytosine

Deoxyribose

Deoxyribose

Fig. 12-6b, p. 267


http://www.thetech.org/genetics/zoomIn/index.html


Fig. 12-9, p. 270


Mutation

Fig. 12-9, p. 270


Exon

Intron

Exon

Exon

Intron

DNA in a eukaryotic chromosome

Transcription

Pre-mRNA

RNA processing (remove introns)

Mature mRNA

Formation of cDNA relies on RNA processing that occurs in the nucleus to yield mature mRNA.

Fig. 15-6a, p. 328


DNA

  • Representa el material de herencia

  • Está localizado dentro del núcleo en los cromosomas.

  • Tenemos 22 pares llamados autosomales 1-22

  • El #23 es el cromosoma sexual: XX y XY

  • En la molécula del DNA hay secuencias de genes

  • Los genes Codifican para proteínas.

  • DNA RNA mensajero proteínas


Relación de DNA y proteínas

  • El DNA se transcribe a m RNA = Transcripción

  • Si el mRNA se traduce a una proteína= Traducción


When genes go bad: Mutations & diseases

  • http://www.thetech.org/genetics/art04_bad.php


Métodosusadospor los geneticistasparaestudiarpatrones de Herencia.

  • Árbol genealógico

  • Cariotipos

  • Ánálisis bioquímico o Metabólico

  • Genética al Reverso ( Genética Molecular)


Árbolgenealógicos

  • Pedigree: representación de los miembros de un tronco familiar a través de diferentes generaciones.

  • Véase símbolos y modelos


Fig. 16-2, p. 349


I

2

3

4

1

II

1

2

3

4

5

III

1

2

3

4

Key:

Mating

Normal female

Normal male

Siblings produced

by mating

Albino female

Albino male

Fig. 16-2, p. 349


p. 366


Herencia

  • Genes autosomales:

    • dominantes  AA, Aa

    • recesivos aa


Herencialigada al sexo

  • Al cromosoma XX

  • Al cromosoma XY


Estudio de Cruces

  • Albinismo autosomal recesivo

  • Hungtinton autosomal dominante

  • Tay Sachs autosomal recesivo

  • Hemofilia ligado al sexo: cromosoma X gen recesivo

  • Daltonismo ligado al sexo gen recesivo


Grupossanguíneos: Alelosmúltiples

  • Grupo A

  • Grupo B

  • Grupo AB

  • Grupo O


  • Genes dominantes: A y B

  • Genes Recesivos: O


Cariotipos

  • Mapa de los cromosomas de un individuo.

  • En humanos, 46 cromosomas.

    • 23 los porta el gameto femenino (Óvulo)

    • 23 los porta el gameto masculino

      ( Espermatozoide)

    • Ambos gametos son haploides= poseen la ½ del total de cromosomas.


AnomalíasCromosómicas

  • Delección: Cromosoma #5 Cri-du chat

  • Cromosomas extras): Cromosoma sexual X O en ..

    • Ejs.

      • hombres Klinefelter XXY

      • Síndrome de Down Trisomía en el par # 21


Otrasanomalías

  • Ausencia de un cromosoma : mujer Turner

    • XO Le falta un cromosoma sexual

  • Traslocación: fragmentos de un cromosoma se desprende y se inserta en otro grupo

    • Ej. Síndrome de Down


  • Fig. 16-1, p. 348


    Fig. 16-1a, p. 348


    Fig. 16-1b, p. 348


    Fig. 16-4, p. 353


    A reciprocal translocation occurs when two non-homologous chromosomes exchange segments.

    Fig. 16-5d, p. 355


    Fig. 16-3, p. 352


    Nondisjunction in first meiotic division

    XY

    XY

    X

    Y

    First meiotic division nondisjunction results in two XY sperm and two sperm with neither an X nor a Y.

    Fig. 16-3a, p. 352


    Nondisjunction of Y in second meiotic division

    Nondisjunction of X in second meiotic division

    Normal first meiotic division

    XX

    X

    X

    X

    Y

    Y

    YY

    Y

    Second meiotic division nondisjunction of the X chromosome results in one sperm with two X chromosomes, two with one Y each, and one with no sex chromosomes. Nondisjunction of the Y chromosome results in one sperm with two Y chromosomes, two with one X each, and one with no sex chromosome (box on right).

    Fig. 16-3b, p. 352


    An inversion is a chromosome segment with a reversed orientation. An inversion does not change the amount of genetic material in the chromosome, only its arrangement.

    Fig. 16-5b, p. 355


    Lost segment

    A deletion is the loss of a chromosome segment. A deletion can occur at the tip (shown) or within the chromosome.

    Fig. 16-5c, p. 355


    1 μm

    Fragile site

    CGG repeats (200 to more than 1000 times)

    CGG repeats (up to 50 times)

    Fig. 16-6, p. 356


    1 μm

    Fragile site

    CGG repeats (200 to more than 1000 times)

    CGG repeats (up to 50 times)

    Fig. 16-6, p. 356


    Fig. 16-7, p. 357


    Fig. 16-9, p. 359


    Fig. 16-11, p. 361


    1

    About 20 mL of amniotic fluid containing cells sloughed off from fetus is removed through mother's abdomen.

    Ultrasound probe determines position of fetus

    16-week fetus

    Uterine wall

    Amniotic cavity

    Fluid is centrifuged.

    2

    Amniotic fluid is analyzed.

    3

    Fetal cells are checked to determine sex, and purified DNA is analyzed.

    4

    Placenta

    5

    Some

    cells are grown for 2 weeks in culture medium.

    6

    Karyotype is analyzed for sex chromosomes or any chromosome abnormality.

    7

    Cells are analyzed biochemically for presence of about 40 metabolic disorders.

    Fig. 16-11, p. 361


    Fig. 16-12, p. 362


    Transabdominal sampling technique

    Withdrawn chorionic villi cells

    Cervical sampling technique

    Ultrasound probe

    Syringe

    Catheter

    Withdrawn chorionic villi cells

    or

    Chorionic villi

    Catheter

    Cells are cultured; biochemical tests and karyotyping are performed

    Fig. 16-12, p. 362


    Análisismetabólicos o bioquímicos

    • Heredados

    • adquiridos


    Desórdenes

    • Tay Sachs: deficiencia de la enzima Hexosaminidasa A

    • Diabetes: deficiencia de insulina

    • Fenilcetonuria: bebés no pueden procesar la fenilalanina. Niveles elevados lesionan el cerebro y causan retraso mental y se diagnostican PKU+


    Otrostrastornos

    • Amiloidosis: acumulación y depósito de proteínas anormales en órganos.

      • Deterioro de órganos


    Genética al Reverso

    • A nivel molecular

    • Identifica genes en los cromosomas

    • Secuenciación del genoma..

      • conocer la secuencia de las millones de bases nitrogenadas en nuestro genoma


    The Human Genome Project

    • Findings

      • Human genome contains ~25,000 genes

      • New genes, including many disease-associated genes have been discovered

      • Has determined the nucleotide sequence of all the DNA in our entire set of genes, called the human genome

      • The genes comprise 2% of all the DNA


    Plasmids


    Cutting DNA with a restriction enzyme


    • Information flow from DNA to protein

      • Transcription

        • RNA molecule complementary to the template DNA strand synthesized

      • Translation

        • Polypeptide chain specified by messenger RNA (mRNA) is synthesized


    • Gene therapy

      • Normal allele is cloned

      • DNA introduced into certain body cells

      • One technical challenge is finding appropriate vector


    • Recombinant DNA methods

      • Restriction enzymes

        • Enzymes from bacteria

        • Used to cut DNA molecules in specific places

        • Enable researchers to cut DNA into manageable segments

      • Vector molecule carrier of DNA fragment into cell

      • Transformation: uptake of foreign DNA into cells


    Producing a genomic or chromosome library


    Chain termination method of DNA sequencing


    • DNA sequencing

      • Based on chain termination method

      • Yields information about

        • Structure of gene

        • Probable amino acid sequences of its encoded proteins


    • Applications of DNA technology

      • Gene therapy

      • Tissue engineering

      • DNA typing


    GM Plants and Medicines

    • Medically useful genes can be inserted into plants—example:

      • Plants could be engineered to produce human antibodies, conferring passive immunity to microbial infection merely by eating the plant


    Section 13.3 Outline

    • 13.3 Biotechnology in Forensics

      • How Biotechnology Revolutionized Forensics

      • Amplification of DNA by Polymerase Chain Reaction

      • Gel Electrophoresis: Separation of DNA Fragments

      • DNA Probes Are Used to Highlight Bands in a Gel

      • DNA Fingerprinting


    Section 13.6 Outline

    • 13.6 Biotechnology in Medicine

      • DNA Technology Can Be Used to Diagnose Inherited Disorders

      • Restriction Enzyme Fragment Analysis

      • Identification of Defective Alleles with DNA Probes

      • DNA Technology Can Be Used to Treat Disease


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