What is Inheritance

How do we inherit traits from our parents? Dogs beget dogs, people beget people, trees beget trees, and platypuses beget platypuses. The point here is that any species has offspring of the same species. Not only that, but the offspring tend to look a lot like their parents. A beagle will not have great dane puppies, it will have beagle puppies. This is because we inherit our genome from our biological parents.

How do we inherit traits from our parents? Let's start again with bacteria because their method of reproduction is the easiest to understand. When a bacterium reproduces it first makes a copy of its genome. After the copy is complete the cell grows more cell wall and membrane and eventually divides into two cells. After the process is done there are two virtually identical bacteria where there was once one. This is bacterial inheritance, the two "daughter cells" have inherited the same genome as the parent.

How do we inherit traits from our parents? Now let's get more complicated and discuss how genomes combine during sexual reproduction. There is still inheritance during sexual reproduction; however, the offsprings' genomes are not just a copy of one parent's, but a combination of two parent's genomes.

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How do we inherit traits from our parents? To understand inheritance in sexually reproducing organisms, one must first understand the makeup of the genome. First off, all sexually reproducing organisms are diploid, meaning they have two nearly identical copies of their genome in almost all of their cells, with an important exception for reproduction. Sexually reproducing organisms produce gametes which are cells that have only one copy of the genome. These gametes are created by the process called meiosis.

Chromosomes

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How do we inherit traits from our parents? During sexual reproduction two gametes, one male and one female, combine their single genomes to make a new diploid cell with two copies of the genome. One copy of the genome from the father, and one from the mother grow together into a new offspring. The two genomes will replicate in the new organism via the process of mitosis. The two genomes will remain side-by-side, but will not mix, until the organism starts to produce gametes for a new round of sexual reproduction. Right before reproduction, during the process of meiosis, the parents genomes finally mix in what is called crossing-over. So even though the gametes only take one copy of the genome, that copy is actually a mixture of the parents' genomes.

How do we inherit traits from our parents? We have described how genes are passed down, and mixed by sexual reproduction. The process helps create genetic diversity, which is important for the survival and advancement of a species. Genetic diversity is important because the more varied a species is, the more likely it can survive in different environments and a wide array of diseases.

About the site: I developed geneticsalive.com as a companion website to cellsalive.com. Everything a cell does is a direct result of the genetics of that cell, whether it is a single-cell organism or part of a much larger organism. Thus, understanding the cells requires an understanding of the basis of all of their behaviors. About the author: I am a microbiologist studying microbial pathogenesis and the host immune response. My studies have included work in many pathogens including Rabies and Influenza viruses, Mycobacterium tuberculosis, Francisella tularensis, and Salmonella enterica. I currently live just outside of Philadelphia, PA, where I work as a postdoctoral fellow researching antigen processing and presentation during rabies infection. My email is always open for suggestions, corrections, or any other comments. Please feel free to contact me: geneticsalive@gmail.com