Why do we have these features?

Introduction

When we talk about the similarities between parents and children, we are in the presence of the result of genetic inheritance, in which characters contained in the genes of the parent are given to their children.

Gregor Mendel established the basic laws of genetic inheritance long before the term "gene" was coined. Mendel made thousands of crosses with different varieties of the pea plant.

 

 

 

 

 

 

 

Task

Who was Gregor Mendel?

Gregor Mendel (1822-1884) is a father of genetics, through his work on pea plants he discovered the fundamental laws of heredity. He deduced that genes come in pairs and are inherited as separate units, one from each parent.

What is genetics?

Genetics is the scientific study of genes and heredity, of how certain qualities or traits are passed from parent to child as a result of changes in the DNA sequence. A gene is a segment of DNA that contains instructions to build one or more molecules that help the body function.

Due to this information, would you like to know how genetic information is given and transmitted between generations?

 

 

 

 

 

Process

Inheritance process

Genetic inheritance is the process by which the characteristics of parents are transmitted to their descendants, whether they are physiological, morphological or biochemical characteristics of living beings under different environments.

Mendel's Laws of Heredity are usually stated as:

1) The Law of Segregation: Each inherited trait is defined by a gene pair. Parental genes are randomly separated to the sex cells so that sex cells contain only one gene of the pair. Offspring therefore inherit one genetic allele from each parent when sex cells unite in fertilization.

2) The Law of Independent Assortment: Genes for different traits are sorted separately from one another so that the inheritance of one trait is not dependent on the inheritance of another.

3) The Law of Dominance: An organism with alternate forms of a gene will express the form that is dominant.

 

Evaluation

Exceptions to Mendel's Laws:

Although Mendel's laws are fulfilled in many cases, sometimes it seems that they are not, since different phenotypic or genotypic proportions are obtained than expected. Some of these exceptions that occur are due to:

Mutations:

Mutations are changes that occur in DNA, which cause new and therefore unpredictable phenotypes to appear.

Lethal genes:

Other times lethal genes appear, causing the death of individuals before they are born or in the first stages of life. This also modifies the expected genotypic and phenotypic ratios.

Quantitative inheritance:

In other cases, the manifested character does not depend solely on a pair of genes, but on several pairs of alleles that contribute, in a summative way, to the appearance of the phenotype. Due to the summative nature of these alleles, many phenotypes appear with small differences between them, being able to order them progressively. An example of this type of inheritance would be the color of hair, skin, or height in people.

Exception to Mendel's 3rd Law:

Linked genes As seen in Mendel's Third Law, genes are passed on to offspring independently of one another. But there are genes that are located on the same chromosome, and these tend to be transmitted together and not independently as Mendel proposed. These characters are said to be determined by linked genes.

 

 

 

Conclusion

Mendel's laws explain the traits of offspring, based on knowledge of the characteristics of their parents. Today his legacy has been the foundation or sustenance of genetics. His experiments even over the years continue to be the basis of work for many scientists.

Credits
Teacher Page

Group members:

  • Danna Antequera
  • Valentina Hernández
  • Meriangel Pacheco 
  • María Patiño
  • Eyleen Pérez
  • Nicole Varela 
  • Judith Vidal

Course: 901