CHROMOSOMESCHROMOSOMES

The packaging for our genesGenes are the instructions used to make functional productsProteins are the basic component of all living cells

CHROMOSOMESCHROMOSOMES

What are they?

In every cell of our body, except for red blood cells

CHROMOSOMESCHROMOSOMES

Where are they?

Can see chromosomes under microscope during cell division

CHROMOSOMESCHROMOSOMES

What do they look like?

CHROMOSOMESCHROMOSOMES

What do they look like?

p arm“petit”

q arm

centromere

telomere

telomere

654321

chromosome region“3p21”

2

1

1

2

46 chromosomes22 pairs of autosomes1 pair sex chromosomes

HUMAN KARYOTYPEHUMAN KARYOTYPE

Which one is the Y?

SEX CHROMOSOMESSEX CHROMOSOMES

Fruit Fly 8

Peas 14

Goldfish 94

Dogs 78

Humans 46

CHROMOSOMESCHROMOSOMES

How many chromosomes do other organisms have?

MITOSISMITOSIS

MEIOSISMEIOSIS

CHROMOSOME DIFFERENCESCHROMOSOME DIFFERENCES

• Down syndrome• Cri du Chat syndrome• Williams syndrome

CHROMOSOMESCHROMOSOMES

What are some disorders that are caused by chromosomal imbalances?

DOWN SYNDROMEDOWN SYNDROME

Photo provided by CDSS

Common Physical FeaturesDecreased muscle tone at birthSimian creaseUpward slanting eyesHeart defectsShorter height

DevelopmentModerate to severe mental retardationDelay in language, cognitive, motor

Treatment

Life Expectancy50% live longer than 50 years.

Impact of this condition on the affected person and their family

DOWN SYNDROMEDOWN SYNDROME

MEIOSIS AGAIN...MEIOSIS AGAIN...

trisomy

Normal Meiosis Abnormal Meiosis: Non-disjunction

CRI-DU-CHAT SYNDROMECRI-DU-CHAT SYNDROME

Photos provided by www.criduchat.asn.au

DELETIONDELETION

TRANSLOCATIONTRANSLOCATION

Reciprocal

46,XX,t(2;17)(q21.3;q25.2)

TRANSLOCATIONTRANSLOCATION

Reciprocal

45,XX,der(13q;14q)

**

TRANSLOCATIONTRANSLOCATION

Robertsonian

• Microdeletion of chromosome 7q11

• “cocktail party” personality

• Moderate to severe learning problems

WILLIAMS SYNDROMEWILLIAMS SYNDROME

A man carries a 21q21q Robertsonian translocation. What is the chance that he will have a baby without a chromosome problem?

QUESTION??QUESTION??