Sex Linked and disorders

Sex Linked and disorders

Mendel Varied Types of inheritance

Epigenetics Misc

Organisms that have two different alleles for a trait are

called …..

ANSWER:

Heterozygous

Name three things a Punnett square can show

ANSWER:

Genotypes of parents

Possible results of the cross

Possible genotypes of the children

Explain complete dominance

ANSWER:

When the dominant allele is present the recessive

allele is masked

Achondroplasia (dwarfism) is caused by a dominant gene. A woman and a man both with

dwarfism marry. If homozygous achondroplasia results in death

of embryos, list thegenotypes and phenotypes of all

potential live-birth offspring.

ANSWER:

2 Aa Dwarfism

1aa Normal

What type of dominance allows all alleles present to be fully

expressed?

ANSWER:

Codominance

In a family of four, 1 child has curly hair, 1 child has straight hair, and 2 children have wavy hair. Show what the genotypes and phenotypes of the parents

would have to be.

What kind of dominance is this?

ANSWER:

Parent 1 – genotype Cc

Phenotype – wavy hair

Incomplete dominance

Two newborn babies were accidentally mixed up at the

hospital. Determine the parents of the babies by blood type.

ANSWER:

Baby 1 Brown

Baby 2 Smith

What type of inheritance is shown by human skin color, height, eye color, etc.?

ANSWER:

Polygenic

What is the difference between multiple alleles and polygenic

inheritance

ANSWER:

Multiple alleles – one gene has more than 2 variants or alleles for a trait

Polygenic – multiple genes ( can be on multiple chromosomes) all

interact to produce a phenotype

Do men or women express sex linked traits more often?

Why?

ANSWER:

Men, they have one X chromosome, thus they only need one recessive

and it is expressed

What are genetic test performed on? (What are valid samples?)

ANSWER:

Blood

Skin

Hair

Amniotic fluid

If you mutate a sequence of DNA which do you alter?

GenomeEpigenomeProteome

ANSWER:Genome

Why can an organism produce more proteins than they have

genes(Ex 20,000 genes and 120,000

proteins)

ANSWER:

Proteins are made up of various combinations of polypetides

Genes code for primary structure

Also modification after transcriptions allows RNA to be “modular” in

function

If two people who are both carriers for a genetically

inherited fatal recessive disease decide to become parents, what

will be the odds that their children will also be carriers?

ANSWER:

50% or 2 out of 4

What attaches to the strand of DNA to inhibit transcription of the gene

ANSWER:

A methyl group or acetyl group

When is the epigenome silenced?

ANSWER:

During the first days after an egg is fertilized

How are histones manipulated to loosen them up and allow the DNA

to be transcripted?

ANSWER:

Acetyl or methyl groups attach to them and the

negative charges repel or attract the histones away

from each other

DAILY DOUBLE

If the human genome is like a computer, what is the epigenome

like?

ANSWER:

Computer Software

The alleles for eye color and for body color are on the X chromosome of

Drosophila, but not on the Y. Red eye color (w+) is dominant to white eye color (w), and tan body color (y+ ) is

dominant to yellow body color (y). What is the genotype of a tan-bodied, white-

eyed male?

ANSWER:

In horses, coat color is often codominant. The chestnut horse carries two chestnut alleles (Cc)The palomino horse carries on chestnut allele (Cc)and one crème allele (Ccr). A horse with two crème alleles is called a cremello. A. If you were to breed a chestnut horse with a palomino what would the offspring be like?

B. What are the possible combinations of parents to get a cremello horse?

ANSWER:A. Chestnut (CcCc)Xpalomino(CcCcr)

50% Chestnut 50% Palomino

B. Cremello X Cremello 100% Cremello

Palomino X Cremello 50% Cremello

Palomino X Palomino 25% Cremello

In a dihybrid cross, the expected ratio in the F2

generation is..

ANSWER:

9:3:3:1

Epigenetics is critical to what process that occurs during very early development of the fetus?

ANSWER:

Cell differentiation

What is a test cross?

ANSWER:

A cross between an dominant phenotype and a

recessive phenotype to determine the genotype of the dominant phenotype

If two parents are heterozygous for a genetically inherited dominant trait, what is the probability that

they will have a child together who has this trait in his or her

phenotype?

ANSWER:

75%

If there is a single pair of alleles that determine the number of toes for an

animal species and homozygous dominant individuals have 8 toes,

heterozygous ones have 7, and homozygous recessive ones have 6, the inheritance pattern would be referred

to as:

ANSWER:

Incomplete dominance

FINAL JEOPARDY

Baldness in humans is a dominant, sex-influenced trait. This gene is on the autosomes, not the sex chromosomes, but how it is expressed is influenced by the person’s sex (due to hormones present, etc.). A man who is BB or Bb will be bald and will be non-bald only if he is bb. A

woman will only be bald if she is BB and non-bald if she is Bb or bb (it’s almost like B is dominant in males and b is dominant in females).

Actually, because of the influence of other sex-related factors, most women who are BB never become totally bald like men do, but rather,

their hair becomes “thin” or sparse. If two parents are heterozygous for baldness, what are the chances of

their children being bald? Use a Punnett square to illustrate this.

Note: because the sex of a person does make a difference in how the gene is expressed, you need to set this up as a dihybrid cross to account for the

sex of the children.

ANSWER:

1/8 of the children will be bald daughters, 3/8 will be normal daughters,3/8 will be bald sons1/8 will be normal sons;

.