concept 3: mutations and pedigrees

Question 1

What is the difference between a mutation in a somatic cell vs. a mutation in a gamete?

Answer 1

Somatic cell mutations occur in body cells and are passed on by mitosis -> cancer (affect you)

Gamete cell mutations (germline mutations) are passed on by meiosis -> mutated offspring (affects your offspring)

Question 2

What is the difference between gene and chromosomal mutations?

Answer 2

Gene mutations happened during DNA replication and cause a change to the original DNA sequence (ex. cystic fibrosis, sickle cell anemia) , while chromosomal mutations often occur during meiosis, changing the number or location of the genes (not the actual gene sequence) (ex. Down syndrome, Klinefelter’s syndrome, turners syndrome)

Question 3

What is the difference between point mutations and frameshift mutations?

Answer 3

Point mutations substitute one nucleotide for another (GAG -> GUG) ex. sickle cell anemia
Caused by replication errors or environmental mutagens

Frameshift mutations are the insertion or delete of a nucleotide ex. ATTACC ->ATACC
ex. ATTAC -> ACTTACC

Question 4

What are the different inheritance patterns for genetic disorders?

Answer 4

Autosomal rescessive
Autosomal dominant
Sex-linked dominant

Question 5

What is a mutation?

Answer 5

any change in DNA

Question 6

What is a mutagen?

Answer 6

chemicals that can cause DNA mutations
ex. Radiation, UV light, cigarette smoke

Question 7

What is duplication?

Answer 7

Changes the size of chromosomes and results in multiple copies of a single gene

Question 8

What is translocation?

Answer 8

pieces of non-homologous chromosomes exchange segments (during crossing over)

Question 9

What is nondisjunction?

Answer 9

chromosomes do not separate correctly during anaphase, resulting in 1 or 3 chromosomes rather than 2 per cell

Question 10

What is a pedigree?

Answer 10

a chart used to trace the phenotypes and genotypes in a family to determine whether people carry diseases

Question 11

How do you find the inheritance pattern of a pedigree?

Answer 11

If way more males than females are affected, then the pedigree is tracing a sex linked trait

Look for 2 parents that are the same shade that have a child who is different from them. Label the child homozygous recessive and the parents heterozygous
If the child was shaded, the pedigree is tracing an autosomal recessive
If the parents were shaded, the pedigree is tracing an autosomal dominant trait