5 Questions
Qual é a principal diferença entre alelos recessivos e dominantes?
Alelos recessivos se expressam apenas quando há duas cópias, enquanto alelos dominantes se expressam mesmo com apenas uma cópia.
Um indivíduo que herda apenas uma cópia do gene anormal para anemia falciforme será:
Assintomático, mas portador da doença.
Qual é a consequência de um indivíduo herdar uma cópia de um alelo dominante?
Ele exibirá a característica associada ao alelo dominante, independentemente de ter uma segunda cópia.
O que acontece quando um indivíduo herda duas cópias idênticas de um alelo recessivo?
O alelo recessivo se expressará e o indivíduo exibirá a característica associada.
O que significa dizer que um indivíduo é $genótipo$ para uma determinada característica?
A combinação de alelos que esse indivíduo possui para essa característica.
Study Notes
Genetics: Genotype, Phenotype, Recessive Alleles, Dominant Alleles
Genetics is the scientific study of heredity and its mechanism, i.e., the passing of traits from one generation to another through genes. It involves understanding how genetic material is transmitted, stored, and expressed within species. Here, we'll delve into essential aspects of genetics, including genotype, phenotype, recessive alleles, and dominant alleles.
Genotype
The genotype refers to the specific set of genetic information that determines the inherited characteristics of an individual organism. In other words, it's the complete set of genes carried by an organism. For instance, humans have approximately 20,000 to 25,000 genes. These genes account for our distinct physical features, such as eye color, hair texture, and height. Additionally, they play a role in determining less observable traits, like susceptibility to certain diseases.
Phenotype
On the other hand, the phenotype represents the observed physical, developmental, or behavioral characteristics of an organism. This includes aspects like body size, shape, eye color, and any other trait resulting from gene expression. A person's phenotype can also reflect their interaction with the environment and nutritional factors, which may influence their appearance or health status.
Recessive Alleles
Recessive alleles are alternate versions of a particular gene. They typically result in a specific trait if both copies of the gene carry this variation. However, these recessive alleles do not express themselves unless an individual inherits two identical copies, one from each parent. An example of a recessive trait in humans is sickle cell anemia, where individuals who inherit only one copy of the abnormal gene will not show symptoms but may become carriers of the disease.
Dominant Alleles
In contrast to recessive alleles, dominant alleles express themselves even when just one copy is present. When an individual inherits a dominant allele from one parent, it overrides the effect of any recessive allele for that trait. As a result, the individual will exhibit the associated characteristic regardless of whether there is a second copy or not. One well-known example of a dominant trait is Huntington's disease, where a single copy of the mutated gene causes the illness.
Understanding genetics helps us comprehend the mechanisms underlying various biological processes and, ultimately, contributes to advancements in medicine and biotechnology.
Explore aspectos essenciais da genética, incluindo genótipo, fenótipo, alelos recessivos e alelos dominantes. Entenda a diferença entre o conjunto específico de informações genéticas que determinam as características herdadas (genótipo) e as características observadas de um organismo (fenótipo). Descubra como os alelos recessivos e dominantes influenciam a expressão de traços hereditários.
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