Download GeneticsPreLab

Genetics PreLab
In living things that reproduce sexually, a set of chromosomes from each parent (or from two sources
in a single parent) go into each offspring. Each set of chromosomes carries more-or-less a full set of
genes, each of which is the "code" for a particular type of protein. Proteins have many, many roles in an
organism, and sometimes a single protein is critical in making a certain obvious trait; however, each
gene comes in a variety of code forms, or alleles, which may produce proteins with identical functions
or very different functions. Each type of protein that an organism makes is a product of the alleles that it
has, so the resulting traits are not only different in a group, but can be different in an individual
depending upon how the two alleles are expressed. Often the resulting trait is a blend of the two alleles’
proteins’ effects, but sometimes one allele’s (a dominant allele) protein produces an effect so powerful
that it can completely cover up the weaker effect of another allele’s (a recessive allele’s) protein. It also
must be noted that a huge number of traits are the product of at least two proteins working together, and
so have many various ways that the alleles involved can mix effects.
This lab will look at some of the more simple properties of basic genetics, the working of genes. It
requires part of your lab work to be done ahead of time. You are going to make up a chart or table to
bring with you to the lab. Each column or line will be a different trait, off the trait list below; running
the other way on the chart will be the people you have surveyed. You need at least ten other people and
yourself on the table, but get as many as you can. Record your data in an easily readable form. You may
not be able to determine everything, but be sure to note where data has not been available with "NA."
Traits List:
WIDOW'S PEAK. This is found at the top center of the forehead - it's a distinct downward point on the
hairline. You either have it or you don't.
EARLOBE. Look for where the lower earlobe attaches to the head - does it hang freely, more like a "U"
(unattached), or curve directly into its attachment on the face, more like a "J" (attached)?
EYE COLOR. Record eye color in as much detail as you want; in the lab, we'll be interested in basic
colors.
EYELASHES. Record either long (over 1 cm.) or short.
TONGUE ROLLER. Someone who can do this can stick out their tongue so it looks like an "O" or "U"
from the front. You either can do it or you can't.
DIMPLES. If present, tell where and how many. Cleft chin counts.
FRECKLES. Looking for facial freckles, enough to be obvious.
HITCHHIKER'S THUMB. When present, the thumb, held up, has almost a right angle bend on the
outside and the pad is almost parallel to the ceiling.
INTERLOCK. When you fold your hand together in front of you, which hand's thumb is on top? (May
not be clearly dominant - recessive trait, but fun to test.)
HANDEDNESS. Recent discoveries make right-handedness dominant over no pre-determination –
folks with two recessives are about 50% left-handed.
LONG PALMAR MUSCLE. Make a tight fist and bend your wrist toward you, to make the tendons
stand out. If three (or more) are clearly there, you are considered to have a long palmar muscle.
MIDDIGITAL HAIR. Almost everyone has hair on the bottom segment of their fingers - you're looking
for a similar patch of hair on one or more of the middle segments of the fingers. A very few
stray hairs aren't enough.
BENT LITTLE FINGER. Put you hands side-by-side, palms up and facing you. Do the tips of the little
fingers seem to point away from each other? If so, you have bent little fingers.
Use the chart on the backside as a guideline.
Copy the chart onto a piece of paper:
Trait
# of people who had trait
Trait
Widows Peak
No Widows Peak
Ear Lobes - unattached
Ear lobes - Attached
Eye Color – Dark
Eye Color - Light
Eye Lashes Long (over 1 cm)
Eye Lashes Short
Tongue Roller
Not a Tongue Roller
Dimples
No Dimples
Freckles
No Freckles
Hitchhikers Thumb
Not bent
Interlock – Right Thumb
Interlock – Left Thumb
Handedness - Right
Handedness - Left
Long Palmer Muscle
Short Palmer Muscle
Mid Digital Hair
No Mid Digital Hair
Bent Little Finger
Straight Little Finger
# of people who had
trait
To make your data collection even more reliable, use colors or symbols to illustrate
similarities between individuals. Examples: related to you, not related, males, females,
ethnic background, ect.