Genetic Traits Lab - Chromosome Abnormalities A few human disease conditions can be traced to visible PDF

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Chromosome Abnormalities
A few human disease conditions can be traced to visible alternations in the number or content of chromosomes. In studying the ways that things sometimes go wrong, we gain a deeper understanding of the nature of chromosomes. Using the human chromosome photographs pro...

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Genetic Traits Part 1: Cat Genetics Using cats as the subject for examination, determine as much as you can about their genes. In some cases you can predict the gene pairs immediately, but most often this will be difficult without knowledge of the traits of the parents or offspring. In this part you will determine the following genotypes of 10 different cats and record your information in the table provided. Procedure: 1. Using the internet, go to www.nehumanesociety.org to see pictures of cats.

2. For 10 cats (or however many are there if it’s less than 10), observe the phenotypes that you see. 3. Using the genotypes listed below, indicate the possible genotypes that would explain the phenotypes for your cats in the table provided. Since none of these characteristics has incomplete dominance a cat with a dominant trait, such as tabby could be AA or Aa. For this situation we would write A? to indicate that we can only positively identify one allele. Sex Dilute color locus If Black is dilute to a blue grey color – dd

Female XX Male XY White hair allele If all white W? If any other color is present ww Tabby coloring is when the cat has more than one color on a single hair, which gives them a striped appearance – animals will be identified as tabby in the description If the cat is tabby A? If the cat is a solid color aa

If orange has been diluted to a cream – dd Otherwise D? The alleles for orange or black coloring are found on the X chromosome. Below are the possible genotypes. If the cat is completely white, we cannot tell what the genotype is for orange and black Completely orange male - XOY Completely black male - XBY Calico/Tortoiseshell female - XBXO Completely orange female - XOXO Completely black female – XBXB Completely white cat - X?X? or X?Y

4. The first cat has been done for you as an example. Fred is a male cat with a solid cream colored coat.

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5. Answer the questions that follow the table to explain your results.

Part 2. Human Genetics Chromosome Abnormalities A few human disease conditions can be traced to visible alternations in the number or content of chromosomes. In studying the ways that things sometimes go wrong, we gain a deeper understanding of the nature of chromosomes. Using the human chromosome photographs provided, complete the table in the worksheet. Use the website http://www.ncbi.nlm.nih.gov/medgen to find out more about each condition.

Gene Abnormalities Most human disease conditions are caused by changes in base sequences within a gene. The reason for this is that most changes in the number or content of chromosomes is fatal. Procedure: 1. Access the website http://www.ncbi.nlm.nih.gov/omim. 2. Look up each trait listed in the table on the Data and Observation sheet. 3. Click on the result that seems to be most related to the disease. 4. Which chromosome was it on? (this can be found by looking for the 15p___ or 15q____, in this case 15 stands for the chromosome number) 5. What is the gene called? (listed in the Omim website table under Gene/Locus) 6. Describe the problems caused by this mutation. 7. How is the disease inherited? Is it on an autosomal chromosome or a sex chromosome? Is it dominant or recessive? (listed in the Omim website table under Inheritance)

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Genetic Traits Data, Observation and Analysis

Name _Frankline Olum

Part 1: Cat Genetics Cat Number

Sex of the Cat

White allele

Tabby

Orange

Dilute

1 – Fred

XY

ww

aa

XO Y

dd

2 - Cherono

XX

ww

aa

XBXB

D?

3 – Kipchoge

XY

ww

A?

XO Y

D?

4 -Onyango

XY

ww

aa

X BY

dd

5- Amina

XX

ww

A?

XO X O

D?

6 -Mohammed

XY

ww

aa

XBXB

D?

7 - Wanjiru

XX

ww

aa

XBXB

D?

8 -Wetangula

XY

ww

aa

XBY

dd

9 - Karanja

XY

ww

aa

XBXB

D?

10- Mong’are

XY

ww

aa

XBXB

D?

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Now that you have generated a data set of information on various genes in cats, you are ready to determine how the various traits may be genetically conferred. Characteristic

Most Common Phenotype

Least Common Phenotype

Most Common Genotype

Least Common Genotype

White coloring

Half of coat coloring

All white coat

aa

Aa

Tabby

Short hair

Long hair

A?

Aa

Orange and black

Short hair

Long hair

XBXB

XOY

Dilute coloring

Short hair

Long hair

dd

D?

Choose one male and one female cat from your table and show what type of offspring they could have. Mohammed(male) X Wanjiru(female) Key: Black- Dominant A White -recessive a Aa X Aa

A

a

A

AA

Aa

a

Aa

aa

With the ratio of 3:1,expect a 75% Black and 25% white.

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Part 2. Human Genetics Chromosomal Abnormalities How are the chromosomes abnormal?

What are the symptoms of the syndrome or condition?

45 and X

One sex chromosome is deleted/missing.

Short with small chin, prominent fold of skin at the inner corners of the eyes, low set ears, webbed neck

M and F

46

Deletion (missing pièce of genetic Materials)of the end of the short (p) arm of chromosome 5

High pitchéd cat like Cry, mental retardation, delayed growth, small head size, spaced eyes.

Translocation

M and F

46

Unusual rearrangement of chromosomes

Can lead to genetic disorders like leukemia, intellectual disability, brain or spinal cord abnormalities, heart defects

6

Klinefelter Syndrome

M

47

Two or more X chromosomes.(XXY)

Poor coordination, breast growth, interest in sexless body hair.

7

Jacob’s Syndrome

M

47

They have an extra Y chromosome (XYY)

Problem with spoken language as well as processing spoken

Set Condition

Sex

Number of chromosomes

1

Normal

F

46

2

Normal

M

46

3

Turner Syndrome

F

4

Cat cry (“Cridu-chat”)

5

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words, weaker muscle, coordination problems. 8

Metafemale

F

47

Has three x chromosomes instead of two(XXX)

Usually do not experience any serious symptoms other than mild like development delays.

9

Trisomy 21 (Down Syndrome)

M and F

47

Extra chromosomes (3 copies) at Chromosome 21

Development delays, distinctive facial appearance, intellectual disability.

10

Leukemia (one type)

47

Chromosomes are translocated.

Often enlarged painless lymph nodes

Gene Abnormalities Genetic Disorder

Chromosome where mutation is located.

Name of the gene

Problems caused by this mutation.

Inheritanc e

Achondroplasia

4p

FgFR3

Short limb dwarfism

Autosomal dominant

Duchenne Muscular Dystrophy

13a

Sgcg

Muscular dystrophy

Autosomal recessive

Fragile X Syndrome

Xa

FMRI

Mild to severe intellectual disability

X-linked dominant

Huntington’s Disease

4p

HTT

Lack of coordination, cognitive decline, behavioral difficulties,

Autosomal dominance

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Autosomal recessive

Phenylketonuria, PKU

12a

PAH

Impaired postnatal cognitive development resulting from a neuro toxic effect.

Sickle Cell Anemia

11p

HBB

Acute illness and Autosomal progressive organ damage recessive

A common misconception is that dominant alleles are more abundant then recessive alleles. Huntington’s disease is caused a dominant allele; however, the disease is rare. Explain how this happens. Employing the word dominant in describing allele must not be taken literally that it is in abundance because even most common Huntington disease affects very few people out of the entire population currently. Therefore, dominant is simply used to mean that the allele is expressed over another allele .

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