Genética
La genética es
el campo de la biología que busca comprender la herencia biológica
que se transmite de generación en generación. Genética proviene de la palabra
γένος (gen) que en griego significa "descendencia".
El estudio de la
genética permite comprender qué es lo que exactamente ocurre en el ciclo
celular, (replicar nuestras células) y reproducción, (meiosis) de los
seres vivos y cómo puede ser que, por ejemplo, entre seres humanos se
transmitan características biológicas genotipo (contenido del genoma
específico de un individuo en forma de ADN), características
físicas fenotipo, de apariencia y hasta de personalidad.
El principal
objeto de estudio de la genética son los genes, formados por segmentos
de ADN (doble hebra) y ARN (hebra simple), tras la
transcripicion de ARN mensajero, ARN ribosómico y ARN de
transferencia, los cuales se sintetizan a partir de ADN. El ADN controla la
estructura y el funcionamiento de cada célula, con la capacidad de crear
copias exactas de sí mismo, tras un proceso llamado replicación,en el cual
el ADN se replica.
En 1865 un monje
estudioso de la herencia genética llamado Gregor Mendel observó que
los organismos heredan caracteres de manera diferenciada. Estas unidades
básicas de la herencia son actualmente denominadas genes.
En
1941 Edward Lawrie Tatum y George Wells Beadle demuestran
que los genes [ARN-mensajero] codifican proteínas; luego en 1953 James D.
Watson y Francis Crick determinan que la estructura del ADN es
una doble hélice en direcciones antiparalelas, polimerizadas en dirección 5' a
3', para el año 1977 Fred Sanger, Walter Gilbert, y Allan Maxam secuencian
ADN completo del genoma del bacteriófago y en 1990 se funda
el Proyecto Genoma Humano
.
Clonación (biología)
Para
otros usos de este término, véase Clonación (desambiguación).
Se deben tomar en
cuenta las siguientes características
En
primer lugar se necesita clonar las moléculas, ya que no se puede hacer un
órgano o parte del "clon" si no se cuenta con las moléculas que
forman a dicho ser.
Ser
parte de un animal ya "desarrollado", porque la clonación responde a
un interés por obtener copias de un determinado animal que nos interesa, y sólo
cuando es adulto conocemos sus características.
Por
otro lado, se trata de crearlo de forma asexual. La reproducción sexual no
nos permite obtener copias idénticas, ya que este tipo de reproducción por su
misma naturaleza genera diversidad.
Herencia genética
La herencia
genética es la manera en que se transmiten, de generación en generación,
las características fisiológicas, morfológicas y bioquímicas de los seres vivos
bajo diferentes condiciones ambientales.
inglish:
Genetics
Genetics deals with the molecular structure and function of genes, gene behavior in context of a cell or organism (e.g. dominance and epigenetics), patterns of inheritance from parent to offspring, and gene distribution, variation and change in populations,such as through Genome-Wide Association Studies. Given that genes are universal to living organisms, genetics can be applied to the study of all living systems, from viruses and bacteria, through plants and domestic animals, to humans (as in medical genetics).
The fact that living things inherit traits from their parents has been used since prehistoric times to improve crop plants and animals through selective breeding. However, the modern science of genetics, which seeks to understand the process of inheritance, only began with the work of Gregor Mendel in the mid-19th century.Although he did not know the physical basis for heredity, Mendel observed that organisms inherit traits via discrete units of inheritance, which are now called genes.
Genes correspond to regions within DNA, a molecule composed of a chain of four different types of nucleotides—the sequence of these nucleotides is the genetic information organisms inherit. DNA naturally occurs in a double stranded form, with nucleotides on each strand complementary to each other. Each strand can act as a template for creating a new partner strand. This is the physical method for making copies of genes that can be inherited.
The sequence of nucleotides in a gene is translated by cells to produce a chain of amino acids, creating proteins—the order of amino acids in a protein corresponds to the order of nucleotides in the gene. This relationship between nucleotide sequence and amino acid sequence is known as the genetic code. The amino acids in a protein determine how it folds into a three-dimensional shape; this structure is, in turn, responsible for the protein's function. Proteins carry out almost all the functions needed for cells to live. A change to the DNA in a gene can change a protein's amino acids, changing its shape and function: this can have a dramatic effect in the cell and on the organism as a whole.
Although genetics plays a large role in the appearance and behavior of organisms, it is the combination of genetics with what an organism experiences that determines the ultimate outcome. For example, while genes play a role in determining an organism's size, the nutrition and health it experiences after inception also have a large effect.
Cloning
Cloning
in biology is the process of producing similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments (molecular cloning), cells (cell cloning), or organisms. The term also refers to the production of multiple copies of a product such as digital media or software.
The term clone is derived from the Ancient Greek word κλών (klōn, “twig”), referring to the process whereby a new plant can be created from a twig. Inhorticulture, the spelling clon was used until the twentieth century; the final ecame into use to indicate the vowel is a "long o" instead of a "short o".Since the term entered the popular lexicon in a more general context, the spelling clone has been used exclusively.
In botany, the term lusus was traditionally used.
In the United States, the human consumption of meat and other products from cloned animals was approved by the FDA on December 28, 2006, with no special labeling required. Cloned beef and other products have since been regularly consumed in the US without distinction.Such practice has met strong resistance in other regions, such as Europe, particularly over the labeling issue.
Heredity
is the passing of traits to offspring (from its parent or ancestors). This is the process by which an offspring cell or organism acquires or becomes predisposed to the characteristics of its parent cell or organism. Through heredity, variations exhibited by individuals can accumulate and cause some species toevolve. The study of heredity in biology is called genetics, which includes the field of epigenetics.
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