Hereditary patterns happen depending on different genes and alleles that are present after reproduction.
The offspring will receive different hereditary genes based on the genes that are present in the parents.
Heredity
People get their looks because they inherit DNA, which is a chemical recipe that gives each person their specific looks.
Each person in a family might look similar because a brother and sister will get their genes from their mom and dad and this will give them similar characteristics.
A trait is the characteristic of specific organisms. A trait that a son might receive from his parents is how tall or how short he is.
Heredity happens when traits are passed from one generation to another. Different organisms inherit different traits when the parents pass their DNA or their genetic information to their children or offspring, during reproduction.
Reproduction
There are basically two different types of reproduction, asexual and sexual. People, animals and plants reproduce sexually, and this type of reproduction helps join specialized cells from the two parents.
The sperm and the egg are the specialized cells, and they are called sex cells.
The sperm and the egg each carry half of the genetic information or the DNA that is needed to make the offspring.
DNA
When sexual reproduction happens, the DNA helps to determine what kind of traits are going to go from one generation to another.
DNA is also called deoxyribonucleic acid. The DNA is a molecule that is large and is found in everything that is living. Each living thing has DNA and the DNA in these living things has a nucleus.
When a cell divides, the DNA is copied for each new cell and this gives the new cell all of the genetic information that is needed in order to produce offspring.
Chromosomes
The DNA structure is extremely long, and it all has to fit inside the nucleus. In order for this to happen, the DNA wraps around proteins and this causes tight coils to form.
These structures, the tight coiled structures that contain DNA, are now called chromosomes.
Each chromosome has information for many different traits that a person will have.
Genes
A gene is part of the DNA that helps decide what the trait will be. Genes are found on the chromosomes since the chromosomes are made from DNA.
Genes help to decide what traits a person will have such as arms and legs instead of fins and tails, fur or hair, what color eyes the organism will have, if a flower will have colored petals or no petals at all, and most other traits.
The genes from the parent help to decide what an organism will look like. These genes come in two or more different forms. The forms are called allele.
Alleles form different traits such as blond or brown hair.
During sexual production, the offspring get chromosomes from both of the parents and this gives each offspring a different or unique set of genes.
When different alleles produce different traits, the genes are described as either genotype or phenotype.
Genotype
Genotype refers to the genes that an organism carries.
Phenotype
Phenotype is the way that the genes are expressed. Phenotype is the physical traits that an organism has.
Dominate traits
Traits that are inherited are usually controlled by a single gene, but the gene can have different forms of the alleles.
The way that an earlobe is shaped or if a person has dimples are the result of a single gene that has two different forms.
During sexual reproduction, the offspring gets two different alleles for each trait, one from each parent and the trait carried by one allele is stronger than the other or dominate.
Dominate means to be stronger than another. The Dominate trait is the trait that is always seen in the phenotype of an organism.
So, this is the trait that has the physical characteristics, such as will the person have blond or black hair. If the organism has the dominate allele, it will show.
Recessive traits
The alleles that are not the strongest are called recessive. A recessive trait happens when two recessive alleles are seen.
If an offspring has one dominant allele and one recessive allele the recessive trait will not be seen and the dominate trait will be seen.
Inheriting
The two or pair of genes is a person’s genotype. The genotype helps to identify the organism’s alleles.
Genotypes are written as two different letters. The Dominate alleles are written as a capital letter and the recessive alleles are written in lower case letters.
If a person has the allele for an earlobe that is not attached, then the unattached earlobe is dominate over the attached earlobe and E could be written to show the unattached earlobe and e would be written to show the attached earlobe.
Since each parent gives one allele for each gene, the offspring can have one of three different genotypes. It could be either EE, Ee, ee.
When a person has the dominate allele then the trait will be seen, because only dominate traits are seen.
Since the unattached earlobe is dominate, the genotypes EE or Ee both have the unattached earlobe phenotype.
Since the attached earlobe is a recessive gene, then it will only happen if the person has two recessive alleles.
Therefore, the genotype for the attached earlobe would have to be ee.
Facts About Hereditary Patterns
- If a person has two recessive genes, then that trait will show.
- If a person has two dominate gene, then the dominate trait will show.
- The allele are different forms of genes.
- Genotype is the organism’s genetic makeup or how the allele combine.
- Phenotype is the organism’s physical appearance.
- The dominate trait is the trait that is always shown in the phenotype of an organism, or the physical appearance of the organism.
- The recessive trait is only seen when the two recessive alleles are present.
What Did You Learn?
- What is heredity? Heredity is when traits are passed down from one generation to the next.
- What must be present for an organism to have a physical trait such as black hair? In order for a physical trait to be seen, the organism must have a dominate gene.
- When is a recessive trait seen? A recessive trait is only seen when two recessive alleles are present.
- What is an allele? An allele is a different form of a gene.
- What are the two types of genes called? The two types of genes are called genotype and phenotype.
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