Class #9: The Laws of Inheritance

Punnett Squares

Please answer these following questions on the blank worksheets provided in this week’s class.

Question #1:

In pea plants, yellow peas are dominant over green peas.

Use a Punnett square to predict the genetic outcome (offspring) of a cross between two plants for yellow peas that yield a small amount of green peas.

Question #2:

The long hair of persian cats is recessive to the short hair of siamese cats. Complete a Punnett Square when a a purebred persian is mated with a purebred siamese cat.

Question #3:

The black coat of persian cat is dominant to the brown and tan coat of siamese. Complete a Punnett Square when a a purebred black persian is mated with a purebred brown siamese cat.

Question #4:

In four o’clock flowers, red plants are purebred for the dominant allele (R) of the gene for flower color. Plants with white flowers are purebred for the recessive (r) allele of the same gene. Plants with pink flowers have one of each of the two alleles. Complete a Punnett square that is expected when plants with pink flowers are intercrossed.

Question #5:

In humans, brown eyes (B) are dominant over blue (b). A brown-eyed man marries a blue-eyed woman and they have three children, two of whom are brown-eyed and one of whom is blue-eyed. Draw the Punnett square that illustrates this marriage.

Suppose one of the brown-eyed children marries someone with blue eyes. Use the second Punnett square to predict their offspring.

Pedigree Charts

Queen Victoria’s Bloodline

Handout

First, let’s take a look at Queen Victoria’s son Leopold’s family. His daughter, Alice of Athlone, had one hemophilic son (Rupert) and two other children—a boy and a girl—whose status is unknown.

Questions

(a) What is the probability that her other son was hemophilic?

(b) What is the probability that her daughter was a carrier? Hemophilic?

(c) What is the probability that both children were normal?

 

Now for the Spanish connection: Victoria’s youngest child, Beatrice, gave birth to one daughter, one normal son, and two hemophilic sons.

Questions

(a) Looking at the pedigree of the royal family, identify which of Beatrice’s children received the hemophilic gene; why can you make this conclusion?

(b) Notice that Beatrice’s daughter, Eugenie, married King Alfonso XIII of Spain and had six children, one of whom was the father of Juan Carlos, the current King of Spain. Would you predict that Juan Carlos was normal, a carrier, or a hemophilic?

Queen Victoria’s third child, Alice, passed hemophilia to the German and Russian imperial families (see Figure 4, next page). Of Alice’s six children, three were afflicted with hemophilia. At the age of three, her son Frederick bled for three agonizing days from a cut on the ear. Eventually, the flow of blood was stanched. But a few months later, while playing boisterously in his mother’s room, the boy charged headlong through an open window and fell to the terrace below. By the evening he was dead from the internal bleeding. Alice’s daughter Irene, a carrier, married her first cousin, Prince Henry of Prussia, and gave birth to two hemophilic sons. Every attempt was made to conceal the fact that the dreaded disease had shown itself in the German imperial family, but, at the age of four, Waldemar, the youngest of the princes, bled to death. The other prince, Henry, died at the age of fifty-six. Alice’s other daughter, Alix, was also a carrier. Had she accepted the offer of marriage from Prince Eddy, or his brother George, hemophilia would have been re-introduced into the reigning branch of the British royal family. But Alexandra (Alix) married Tsar Nikolas II instead and carried the disease into the Russian imperial family. She had four daughters, Olga, Tatiana, Marie, and Anastasia, before giving birth to the long-awaited son, Alexis, heir to the Russian throne. These children, along with their parents, were eventually murdered during the Russian Revolution. Within a few months of his birth, his parents realized that their precious and only son, Alexis, had hemophilia. The first sign had been some unexpected bleeding from the navel, which had stopped after a few days. Much more serious, however, were the dark swellings that appeared each time the child bumped an arm or a leg. And worst of all was the bleeding into the joints. This meant a crippling of the affected limbs in addition to excruciating pain. As the boy grew older, he was obliged to spend weeks in bed, and after he was up, to wear a heavy iron brace.

Questions

(a) What are the probabilities that all four of the girls were carriers of the allele hemophilia?

(b) Supposing Alexis had lived and married a normal woman, what are the chances that his daughter would be a hemophiliac?

(c) What are the chances his daughters would be carriers? (d)What are the chances that his sons would be hemophiliacs?

In 1995, a sixty-three-year-old man named Eugene Romanov, a resident of the former Soviet Union, turned up. He shared both the disease and his last name with the royal family of czarist Russia. He proclaimed himself a grandson of Nikolas II’s youngest daughter, Anastasia, whose body had at that time not been recovered, and who was believed by some to have managed to survive the revolution. Eugene Romanov claimed Anastasia was raised by a farmer, and later she married a nephew of her adopted parents and had a daughter, Eugene’s mother.

Questions

(a) According to Eugene’s argument, what was the likely hemophilic status of Eugene’s mother and grandmother? What about his father and grandfather? Is this argument plausible?

(b) How plausible is it that Eugene inherited both hemophilia and the last name from the royal family? (Hint: Look how each of them is passed from generation to generation.)

5. Prince Charles is the designated next king of England. His well publicized marriage to Princess Diana produced two sons before it ended in an acrimonious divorce.

Question

If you learned that one of the two sons was a hemophiliac, what are the possible explanations for this event?

 

Homework

Here are some good Punnett practice problem sites. In fact, the problems above (and likely the questions on the midterm) come from these sites.

The Association for Biology Laboratory Education has a really good .pdf handout on the step by step procedure to solving Punnett square problems.Here is my own list:

If you’re daring, try the challenging Berkeley University problems (the answers are here)

So practice, practice, practice… Bring any problems you have difficulty with to class, and we’ll work them out together.

Class #4: Cladogram!

So far, we have considered how broad the definition of life is, inhabiting moons and planets in our solar system, at least 10,000,000 exoplanets in our Milky Way galaxy, one of 176 billion galaxies in a universe 13.8 billion years old. We can analyze starlight, measuring its spectrums to identify chemical precursors for life, chemicals that react with each other to yield energy for living organisms, without light or oxygen. Life can thrive on Earth three miles deep in our oceans near hydrothermal vents spewing arsenic and sulfuric acid at 250° F. We can draw lines in the sands of 4 ½ billion years, marking geological periods of the Earth’s time in this universe. Scientists know these facts from using space telescopes, geologic strata, carbon-14 dating, and DNA clocks.

We then quickly turned to genetic technologies, due to the plethora of news stories last week about DNA barcoding and 3-Person babies.  The chromozomic conundrum of designing babies, identifying genetic disorders on the human karyotype gene map, down to the cytogenic and molecular locations.

In tonight’s class, we will learn a poquito of scientific language, namely naming elements and chemical compounds.  We will then learn how to translate DNA nucleotides into protein amino acid chains.

HaeckelThe big topic tonight will about the “Tree of Life.” Cladograms of species, like karyotypes, allow us to spatially arrange pieces of information to tell a large story.  Life change over the geological history of Earth — early on, the first living things developed into three categories, or domains, known as Bacteria, Archaea and Eukarya. In later geological periods, each of the Domains developed subdivisions, or Kingoms, one of which circumscribes all animals (Animalia).  Here’s how the entire classification process works.  And here are 3 examples.  Finally, here are two websites that describe DKPCOFGS in depth:

Next week, you will be sharing out the results of your homework assignments to the class.  The rubric follows.

rubric

 

Some Midterm questions will be based on these student presentations.  So take good notes.  Finally, tonight’s homework.

Homework #4


  1. Identify the DKPCOFGS of the species you chose for Homework #2.
  2. Complete the DNA translation worksheet.
  3. Translate the inorganic chemical formulas into words.

Extra credit:

  1. Once the professor says your Genetic Disease form is completed correctly, do another.
  2. Find a news article about thermophiles or extremephiles.

Class #3: DNA Technos Rule the News

I’ve decided to jumble the content today due to two news flashes this week:

  1. DNA barcoding.  This genetic technology is so simple, even even high school kids can use it to identify “sheep’s milk cheese” made from cow milk, “venison” dog treats made from beef, and “sturgeon caviar” that was actually Mississippi paddlefish.  It can be used to identify illegal wildlife trafficking and track food brands.  But yesterday, the technology was used by the New York State Attorney General’s office to conclude that:

    … top-selling store brands of herbal supplements at four national retailers — GNC, Target, Walgreens and Walmart — and found that four out of five of the products did not contain any of the herbs on their labels. The tests showed that pills labeled medicinal herbs often contained little more than cheap fillers like powdered rice, asparagus and houseplants, and in some cases substances that could be dangerous to those with allergies.

    Gingko, St. John’s Wort, and Echinacea were some of the species test for in the branded herbal supplements.

  2. 3-Person Babies” are now legal in the U.K.  Ethical issues such as “designer babies” are associated with such genetic technologies.

Tonight we’ll learn about the basics: DNA transcription/translation, mitosis, and the relationship between DNA, genes, chromosomes and genomes/karyotypes.  More importantly, we’ll pursue the ethical issues involved with genetic technologies and genetic disorders.  We’ll use the movie, GATTACA as a reference point for the class homework.

Homework #3

Suppose you and your mate are going to have a baby.  Answer the following questions, reflecting upon what we discussed in class.

  1. For your in vitro baby, would you
    1. Want to know if your fetus had genetic disease
      1. Severe, Life threatening
      2. Appearance based – skin/eye color, baldness
      3. Behavior based – alcoholism, psychotic, depression

       

    2. Terminate/remediate – gene therapy
  2. For you, would you
    1. Want to know which genetic diseases you are predisposed to
    2. Want gene therapy

Additionally, complete one genetic disorder worksheet, using the Genetics Home Reference website, the OMIM reference number and GeneCards to complete the worksheet.

Finally, find a news article about genetic technology (preferably one of the ones discussed in class) that you find interesting, summarize it, and include its URL (http://…) in a comment to this post.

Class #2: Earth Eras Evolve

So far, we have looked at possible life-supporting exoplanets.  As of yesterday, the oldest Earth-sized planet, currently named Kepler-444, we know of in the Milky Way is over 11 billion years old.  For the rest of this course, we will focus our attention towards life on our planet, Earth.  Our Earth is a youthful 4 1/2 billion years old.  We know its age because the oldest rock on its surface has been found in Jack Hills, Australia. Zircon 74 is 4.37 billion years old.  Formed a mere 160 million years after the formation of the solar system, its ancient existence proves that almost as soon as the Earth formed, there were seas if not oceans of liquid water on its surface, one of the essential building blocks of life.

Geologists have delineated different Eons, Eras, Periods, and Epochs of the Earth’s life to help identify key stages in the evolution of life on this planet.

Color_RGBEmulator6_Oct2010

The zircon crystals mentioned above were formed in the Archean Eon (3.8 — 2.5 billion years ago).  Before the end of the Archean Eon, life had been established through the planet.  Stromatolyte fossils have been dated back to 3.5 billion years ago.

The Miller-Urey experiment is a way of showing how early life on Archean Earth may have been formed. This experiment is one of the fundamental chemical reactions included in the study of exobiology.  That is, all of the the chemical reactants used to produce amino acid products are known to exist in outer space.  An alternative hypothesis for the origin of life is that these chemical reactions occurred miles below the Earth’s surface, where thermophiles and extremxozymes lurk.

The beginning of the next Eon, the Proterozoic, offered evidence of new biochemical reactions, primarily resulting in vast ranges of banded iron, the diagenesis of iron minerals throughout the Earth.  “Snowball Earth” then ensued.  And yet, 100 million years later, 635 million years ago, life not only survived, but diversified into multicellular organisms, in the Ediacaran Period.

Each of the millions of Earths in our Milky Way galaxy has its own epochal story to tell, if we ever set foot on them.  For now, we are limited to exploring the stories our own Earth has to tell.

Homework #2:

We ended class in the Ediacaran Period.

  1. Working in pairs, choose another, more recent period to research.
  2. Type in your choice as a comment to this post (first comment gets it)
  3. Begin researching the forms of life that existed on Earth during that period of time.  Post any interesting websites as additional comments.
  4. Organize your research by the 7 Properties of Life defined on page 2 of your textbook (Miller, 7th Ed.)

Class #1: ¿Que Es La Vida?

georgeGeorge Harrison tells us that life without love is meaningless.  We can debate the relationship between those two four-lettered L-words, but there can be no doubt that our emotions cloud our perspective as to what life is, and is not.

Life must be contained within the boundaries of the universe. The mechanical eye of Planck space telescope has focused on the afterglow of the Big Bang, allowing scientists to calculate its age to be 13.82 billion years old. During its life a billion trillion stars forming the hundreds of billions of galaxies , many viewed by the Hubble, Herschel and Spitzer space telescopes, flying through the night skies.  Tens of millions of life sustaining worlds may exist in our Milky Way galaxy alone. Given there are in our universe.  1,804 confirmed planets, eight of them discovered a couple of weeks ago, believed to be in the “Goldilocks” zone.  Many more are archived.

What about life in our own solar system? Water even exists on Mercury, where the average temperature is over 332 degrees Fahrenheit. Methane is periodically released from Mars, and its rock strata suggests a time where water flowed freely on its surface.  Of our 336 moons, IoEuropa, and Enceladus are likely to harbor life.

Where else can we find life?  Another moon or exoplanet?  Tell me something I don’t know, and post comment below with a link and your name.

Gliding out on the rings of Saturn

Encedalus, Titan and the rings of Saturn

rings

I learned something new this year, we all did. It started with a picture from NASA in 2012, but its full meaning wasn’t revealed until this year, in magazines like Scientific American and Nature.  When I showed the picture above to my students, I realized after half a minute that they didn’t understand what they were seeing: Saturn’s rings on their side, its moon, Enceladus in the foreground, Titan in the background, and a tiny moon to the right of its rings.  In the future, our kids will see it, know it, as if we always knew what it is, when the truth is we only saw for the first time this year, and a lot of us couldn’t make sense of it.

galileo's drawing of Saturn's ringsThe first person to see Saturn’s rings was Galileo Galilei.  When he drew what he saw, even he couldn’t figure out he was looking at rings. More importantly, simply drawing a heavenly object going around another heavenly object was heretical. The notion that something (the rings) went around something other than the Earth (Saturn) violated a millennium of church doctrine and during the Inquisition, that was a very bad thing.  Galileo was led to the church dungeons, and was forced to view torture instruments, the unspoken word being that he would feel them as well if he did not recant. He did, and then, as the story goes, mumbled eppur si muove — “and yet it moves.”

Eventually the church police power waned, although it’s flexing its muscles against scientific facts more and more these days.  Once it was OK to see Saturn’s rings, for four hundred years we wondered how they got there.  And then this year the Cassini spacecraft scanned Enceladus, and radioed back the data which gave us the answer: the moon has an underground lake that may even nurture life.

lake

Can you imagine standing on one of Saturn’s tiny moons, watching Saturn’s massive weight pull and squeeze Enceladus like a mother’s hands on her pimply child’s face until some subterranean mist squirts out from an underground lake, wafting into Saturn’s rings? And that the accretion of geysered mists from Enceladus over four billion years formed Saturn’s rings? Every day, year, century, millennia, we see, first not understanding or accepting something new about the rings, rings a couple of billion years in the making.  The rings will always defy human understanding, a promise that what we think we know now will change, that the mysteries of the universe will continue to surprise us, shock us into new ways of viewing our world and others.

I was in downtown Brooklyn today, at WordCamp NYC 2014, maybe that’s why I heard Walt Whitman’s words wafting down the streets:

WHEN I heard the learn’d astronomer;
Encedalus methane plumeWhen the proofs, the figures, were ranged in columns before me;
When I was shown the charts and the diagrams, to add, divide, and measure them;
When I, sitting, heard the astronomer, where he lectured with much applause in the lecture-room,
How soon, unaccountable, I became tired and sick;
Till rising and gliding out, I wander’d off by myself,
In the mystical moist night-air, and from time to time,
Look’d up in perfect silence at the stars.

Thanks Walt, you made my day.