Tag Archives: genes

The Improbability of You: Meiosis Part One

31 Jul

In this video, we talk about how improbable it is that you exist, the durability of genetic information across time, your relatedness to all living this on earth, and your uniqueness. These concepts will lay the foundation for explaining meiosis — the cellular dance that makes you a mosaic of your ancestors who is different from everyone else, even your siblings.


Nurture begins in the womb

25 Aug
Epigenetics is the study of the chemical reactions that govern which genes get turned on or off. Wikipedia image credited to the National Institutes of Health (NIH).

Am I hungry? Have I just gotten sloshed? Am I in outer space?

All of these factors affect how I am feeling, and less obviously, how my genes are functioning.

If I am a pregnant lady, factors like these become critical because they impact the activation and silencing of genes that coordinate the delicate orchestration of my baby’s development.

Remember, genes are the same in all of our cells, but our cells and body parts look and behave differently because certain genes within them are switched on or off. And in order for the cells of a developing embryo to emerge is a person, genes need to be switched on and off at just the right moment.

What’s controlling these switches? It’s not the genes themselves. Epigenetic signals –(click this for great videos and articles on epigenetics from the University of Utah’s Genetic Science Learning Center) –are the conductors that cue genes in and out at just the right time. They change in function of what we eat, smoke, breathe and drink. _Read on

Lady Gaga Revisited: How one cell becomes an entire person

3 Aug

DISCLAIMER: This latest entry has not yet been rubber stamped by the White Coats who check this blog for scientific accuracy. Corrections to lies below will come soon.  Reader comments, questions and corrections are welcome.

Months ago we began this blog by introducing a puzzle:

As if by wizardry, Lady Gaga arose from a single cell that was smaller than the period at the end of this sentence.  This ought to strike us as incredible, not only because Lada Gaga is composed of trillions of cells, but because her cells have various features and functions, so that her eye balls are distinct from her tuchus.  And yet the cells in her body, whether they make up her liver, legs or lashes, all contain the exact same DNA.

If somehow Lady Gaga had only type of cell—that is, she had grown to full size with cells that never “differentiated,” – we postulate that she would look something like the Fruit of the Loom grape man.

That is to say, she would be a blown up version of the blob she was when she was about 32-cells big, making her way toward her mother’s uterus by way of the fallopian tube.  The sac of cells at this stage is called the morula, latin for mulberry, because it looks like a cluster of seeds.

So why isn’t Lady Gaga a grape man?
Read the answer

How we die

25 Jul

The shiny dots at the ends of these chromosomes are telomeres, the shortening "bomb fuses" that give cells expiration dates. Photo from the U.S. Department of Energy Human Genome Program

All roads lead to death, and we should all hope to take the scenic route.

                Some of us will pickle ourselves: We can smoke, drink, and burger our ways into Heaven.  Some of us will arrive instantaneously, let’s say, while texting.  But most of us will approach death along some kind of BINGO model.  One example:

                B: We’ve got atherosclerosis, or clogged arteries.

                I: We were born with something, like a propensity for high cholesterol.

                N: We have high blood sugar levels; G: We’re not exercising;  O: That one last cigar.

You’re expected to live about 48 million minutes: You’ve got time to read on!

How am I different from my dog?

14 Jan

Fergus smiles

It is not our differences that divide us. It is our inability to recognize, accept, and celebrate those differences.” –Audre Lorde

My dog, Fergus, is furrier than I am. He detects smells more capably, and with a wetter nose. And, this one’s a biggie, words never come out of his mouth.

But while genes help explain the diversity of life on our planet, they show us to an astonishing degree that all we living things are similar.

Gene for gene, people are said to be more than 99 percent similar, one guy to the next. Related genes in humans and apes are almost as alike. We begin to see more differences when we compare the human genome to the genomes of other animals, like dogs and mice, but not much. The related genes of mice and men are roughly 85 percent the same. Good blog. Fetch!

What are my genes (and proteins) doing now?

22 Oct

Courtesy of the U.S. Department of Energy Genome Programs, http://genomics.energy.gov

Genes need to live in almost all of my cells because without them, those cells could neither function nor replicate.

Making new cells, making proteins

Through mitosis, my older cells are, right now as I write this sentence, duplicating their genetic information so that they can split into two “daughter” cells, keeping my body fresh. The dead skin cells I rubbed off in the shower this morning revealed younger, genetically identical cells that, because of mitosis, were there to replace what my loofah scraped away. Continue reading

Cheat Sheet: Genes, Chromosomes and DNA

25 Sep

Nature is the type of cook who is lost without her recipes. Chromosomes are cookbooks, and we have two editions of each.  The recipes are genes.

When we talk about our genes, we are talking about the packages of biological information that we inherit from our parents, and less directly, from our millions of ancestors.

According to the researchers who mapped the human genome, a person has about 20 to 25,000 genes.

Our genes are made up of DNA (deoxyribonucleic acid) strung together by the millions to make thread-like strands called chromosomes at the center (nucleus) of almost all of the trillions of cells in our bodies.

We have 46 chromosomes–23 from mom, 23 from dad.  Each set (mom’s and dad’s) contains only slightly different versions of the same genes.  Technically, each version is called an allele (pronounced uh-LEEL).

Our bodies read our genetic “recipes” in order to cook up amino acids that are the building blocks of proteins.  Proteins, in turn, help our bodies to form, grow, heal, move and function.

Explore the “Cheat Sheets” category to read index cards covering the basics of genetics.