Week 13. Genetics and Inheritance Lab.

Part 1.

Flip-a-coin (or let's make a baby)

	Allele(s) from Mother	Allele(s) from Father	Genotype	Phenotype
Sex of child:		b	XY	Boy
Face shape	r	R	Rr	round
Chin Shape (I)	V	v	Vv	very preminent
Chin Shape (II)	R	r	Rr	round
Cleft chin	A	A	AA	absent
Skin color	abcd	AbcD	AabbccDd	very light brown
Hair type	c	c	cc	straight
Widow’s Peak	w	W	Ww	present
Eyebrows (I)	b	b	bb	fine
Eyebrows (II)	N	n	Nn	not connected
Eyebrow color	H	h	Hh	same color as hair
Eyes distance apart	e	E	Ee	average
Eyes size	E	e	Ee	medium
Eyes shape	A	a	Aa	almond
Eyes slant	H	H	HH	horizontal
Eyelashes	L	L	LL	long
Eye color	abcD	aBCD	aaBbCcDD	light brown
Mouth size	m	M	Mm	average
Lips	l	L	Ll	thick
Protruding lower lip	h	h	hh	absent
Dimples	d	d	dd	absent
Nose size	N	N	NN	big
Nose shape	r	r	rr	pointed
Nostril shape	r	r	rr	pointed
Earlobe Attachment	f	F	Ff	free
Freckles on checks	F	F	FF	present
Hair color	aBcD	abcd	aaBbccDd	blond

Now let's see what this child will look like! As you all know, by now, I am not an artist, but I will try to do my best on drawing this child as he grows and reaches age 16.

And here you go. I hope he doesn't scare you too much; but because he is my "creation" I love him just the way he is.

Part 2.

Genetics problem calculator.

1.       For each of the diploid genotypes presented below, determine the genetic make up for all of the possible gametes that would result through the process of meiosis. Remember, each egg or sperm must have one of each letter. That letter can be upper or lower case.

a.       Rr            Rr

b.       RrYy       Rr, RY, Ry, Yr, Yy, ry.

c.       rrYy        rr, Yr, Yy, ry.

d.       RrYY      RY, Rr, YY, Yr

2.       For each of the following, state whether the genotype of a diploid or haploid cell is represented.

a.       D     - Haploid

b.       GG   - Diploid

c.       P      - Haploid

d.       ee     - Diploid

3.       Yellow guinea pigs crossed with white ones always produce cream-colored offspring. 

      Two cream colored guinea pigs when crossed produced yellow, cream and white offspring in the ratio of 

      l yellow: 2 cream: l white. 

     Explain how are these colors inherited?  No calculations needed! Name the type of inheritance this represents.

Because the cream guinea pigs carrying both white and yellow alleles, their offsprings are inheriting these traits and becoming the color of the dominance. 

Thatis is an incomplete inheritance

4.       In sheep, white is due to a dominant gene (B), black to its recessive allele (b). A white ewe mated to a white ram produces a black lamb. What are the genotypes of the parents? You might need to construct Punnet squares experimenting with different crosses to come up with this answer. Name the type of inheritance this represents.

Even though both parents ar white, they carry the recessive black allele that will show
itself, eventually, by producing a black lamb.

This is a recessive inheritance.

5.       In peas, yellow color (G) is dominant to green color (g). A heterozygous yellow is crossed with a green. What is the expected phenotype ratio of the offspring? Name the type of inheritance this represents.

The dominant yellow peas possess the green alleles that become noticeable by the green
color of its offsprings. There is a 50/50 chance for this type of phenotype. 

That is a dominant inheritance

6.       White color (Y) is dominant to yellow color (y) in squash. A heterozygous white fruit plant is crossed with a yellow fruit plant. What is the expected phenotype ratio of the offspring? What is this type of inheritance called?

As with the yellow and green peas, the squash will illustrate the dominant inheritance and
there will be a 50/50 chance to see them white or green.

7.       In certain flowers, a cross between homozygous red and a homozygous white will always result in a pink flower. A cross is made between two pink flowers. What is the predicted phenotype ratio of the colors red, pink and white appearing in the offspring? What is this type of inheritance called.

Because all of the pink flowers carry one of each of the alleles from white and red, their
offsprings will have a 1/4, 1/2, 1/4 ratio for the white, pink and red colors. (or 1:2:1)

This is an exemple of incomplete inferitance. 

8.       In humans, the condition for normal blood clotting dominates the condition for non-clotting or hemophilia. Both alleles are linked to the X chromosome. A male hemophiliac marries a woman who is a carrier for this condition. In this respect, a carrier is a woman who has an allele for normal blood clotting and an allele for hemophilia. What are the chances that if they have a male child he will be normal for blood clotting? What is this type of inheritance called?

I believe that the male child will have a 50/50 chnce of having a normal blood clotting. 

This is a sex-linked inheritance.

9.       A person with an allele for type A blood and type O blood marries someone with an allele for type B blood and type O blood. List the types of offspring they could have and the probability for each blood type in the offspring. (A allele = I^A, B allele = I^B, O allele = i) What is the expected phenotype ratio of the offspring? What is this type of inheritance called?

Because A and B blood types are dominant, when both A and O present, A will dominate.
According to the Punnet square, The chance of having one of four possible combinations is 1:4.

This is an example of codominant inheritance. 

10.      Skin color in humans becomes darker by the number of dominant alleles; AABBCC have the darkest skin and aabbcc have the lightest skin. Place these genotypes in sequence according to the color of skin expected for each. Place the darkest skin first. What is this type of inheritance called?

Genotypes: AaBbCc, AAbbcc, aabbCc, AaBBCc, AaBBCC.

Because there are many possibilities and variations, this iheritance is called polygenic.