This Punnet square shows to possible combinations of genes in the children of parents that both have the genotype "Ee".
Click on image for full size
Windows to the Universe original image
Answers to the Genetic Puzzle!
- Mary must have two recessive genes to have attached earlobes, so her genotype
- If Mary inherited a recessive gene from each parents, then both of her parents
must have the recessive gene “e” in their genotypes. However,
if both of them have free hanging lobes, then they must also have the dominant
gene “E”. So, both parents must have the genotype “Ee”
- If Fred also has free hanging lobes, the dominant trait, then at least one
of his genes must be dominant (“E”). Did you figure out the possibilities
for the other gene based on the parents’ genotypes? The picture at the
left shows what the Punnet Square looks like.
With two parents that have the genotype Ee, there are three possible outcomes
for the genotypes of the children.
- One out of four (or 25%) will likely have the genotype “ee”
- Two out of four (or 50%) will likely have the genotype “Ee”
(free hanging lobes)
- One out of four (25% will likely have the genotype “EE” (also
free hanging lobes)
So, Fred could have a genotype of “Ee” or “EE”!
Last modified April 13, 2004 by Lisa Gardiner.
Shop Windows to the Universe Science Store!
"Science, Evolution, and Creationism
", by the National Academies, provides fascinating background on these topics for all, and is particularly useful for the Earth and space science classroom. Check our other books
in our online store
You might also be interested in:
Jupiter's atmospheric environment is one of strong gravity, high pressure, strong winds, from 225 miles per hour to 1000 miles per hour, and cold temperatures of -270 degrees to +32 degrees (freezing temperature)....more
In July, 1996, it was announced that Dr. David McKay, along with a team of scientists at Johnson Space Center (a division of NASA), had discovered possible fossils of bacteria in a meteorite named ALH84...more
Saturn's atmospheric environment is one of strong gravity, high pressure, strong winds, from 225 miles per hour to 1000 miles per hour, and cold temperatures of -270 degrees to +80 degrees. With winds...more
Titan's atmosphere is a lot like the Earth's, except that it is very cold, from -330 degrees to -290 degrees! Like the Earth, there is a lot of Nitrogen and other complex molecules. There also may be an...more
Autotrophs are organisms that can "make their own food" from an inorganic source of carbon (carbon dioxide) given a source of energy. Most autotrophs use sunlight in the process of photosynthesis to make...more
In the warm primordial ocean, aggregates of amino acids, proteins, and other hydrocarbons came together into a form called *coacervates*. Amino acids will spontaneously form coacervates in the same way...more
Over a very long time, gradual changes in the earliest cells gave rise to new life forms. These new cells were very different from the earlier heterotrophs because they were able to get their energy from...more