Unit 5 Heredity PDL- The B. mosa

By: Dakoda, Ronnie, Val, and James

How can genetics impact the evolution of a species?

This can be divided into categories:

-Role of DNA in genetic inheritance

-Impact of chromosomal mutations on evolution of a species

-The outcomes of genetic crosses of a species

-The role of meiosis in the evolution of a species

-The results of genetic techniques to show the evolution of a species

Role of DNA in genetic inheritance

-DNA(deoxyribonucleic acid) is a molecule consisting of nitrogen bases, sugars, and a phosphate base that holds the genetic information of an organism.

-Traits are the physical features of an organism defined by its DNA.

-An allele is variant form of a gene.

-An genotype is the collection of genes in an organism.

-An phenotype is the organism's "outside" traits.

-Dominant trait is the allele that "covers up" the recessive trait

-Recessive trait is the allele that is being "covered up."

-DNA is organized into 4 nitrogen bases: A, C, G, and T

-The nitrogen bases of a DNA are ACGT (Adeline, Cytosine, Guanine, and Thymine).

-The nitrogen bases, across, are bonded by hydrogen bonds and between are bonded by sugar-phosphate backbone.

-The order of the DNA determines an organism's trait.

For example:


-DNA is compacted into chromosomes which are the carriers of genes, either dominant, recessive, or both (heterozygous).

-Also DNA are carriers of an organism's genotype and phenotype.

-The splitting of chromosomes during meiosis also contributes the fact why organisms tend to have both traits from their parents.

-This is possible because the sperm and egg are haploid, which they can only pass down one half of their genetic information during meiosis.

5 types of chromosomal mutations

Chromosomal Mutations

Chromosomal mutations can change the genetic code of a trait that is being passed down to an offspring. Most of the time, that mutation is carried on throughout the process of evolution for that species. The mutation, however, can be negative or positive in some way.

Chromosomal mutations can contribute in natural selection only if the mutations are present in the organism's phenotype. With this, only the fittest with the mutations survive as the un-fittest perish. So only the fittest with the mutations can pass their genetic information to their offspring.

Some examples of chromosomal mutations are the change of color of flowers and the change of fur colors of an animal.

Due to natural selection, an organism with mutations that allows it to be the fittest also allows it to dominate the species over time as those not fitted die off.

Meiosis/Sexual Reproduction

Meiosis: a type of cell division where the daughter cells consist half the number of chromosomes from each parent.

Sexual Reproduction: Two gametes( sex cells) fuse together and create an offspring.

During meiosis, the exchange of genetic material between homologous chromosomes that results in a recombined chromosomes during sexual reproduction is called crossing over.

Meiosis allows genetic variation to increase as evolution goes on. Since a parent can pass only half of their genetic information, then genetic variation throughout the species increases. Also meiosis may provided some improvement for organisms in the species that allow them to survive better than the others.


Karyotypes: number and appearance of how many chromosomes there are in a offspring.

Pedigree: a chart used to show the occurrence and appearance of phenotypes of an particular gene in an organism over time.

In chromosomal analysis, it evaluates the number of chromosomes in a person to detect any malfunctions.

Using techniques such as karyotyping can help identify both numerical and structural changes of chromosomes in an organism.

Some patterns in pedigrees are that females are circles and males are squares. Also that a colored square or circle means that the male or female has the phenotype for that gene, either homozygous recessive, or homozygous dominant.

In karyotypes, an extra chromosome often emphasizes that the offspring will have a genetic disorder. An example of this is down syndrome.

Allele Combinations

Mendelian genetic crosses: the dominant trait will always "cover up" the recessive trait when crossing over.

Non-Mendelian genetic crosses-

Co-Dominance: Both the recessive and dominant traits "blend together."

Incomplete dominance: Both recessive and dominant traits are combined but not blended for example, dots on a white sheet.