Mutaions and Pedigree

Question 1

What is Mutations ?

Answer 1

any change in DNA (the order of nucleotide bases/letters)

Question 2

What is mutaions caused by ?

Answer 2

Mistakes made during DNA replication, mitosis, meiosis, or protein synthesis

Question 3

Mutagens

Answer 3

chemicals that can cause DNA mutations Ex. radiation, UV light, cigarette smoke
Viruses

Question 4

Are mutations always bad?

Answer 4

no

Question 5

2 types of Mutaions

Answer 5

1)Gene mutations
2) Chrmomosme mutaions

Question 6

Gene mutations

Answer 6

happen during DNA replication = A change to the original DNA sequence
Ex. Cystic Fibrosis, Dwarfism, and Sickle Cell Anemia

Question 7

Chromosme mutaion

Answer 7

happen during meiosis = Changes the number or location of genes Ex. Down Syndrome, Klinefelter’s Syndrome, Turner’s Syndrome

Question 8

What else is about genes mutaion ?

Answer 8

Point mutations: substitute one nucleotide for another
ATTACC🡪 AATACC

Frameshift mutations: the insertion or deletion of a nucleotide
ATTACC 🡪 ATACC (deletion)
ATTACC 🡪 ACTTACC (insertion)
These will affect all the codons that come after the insertion or deletion

Question 9

What else is about Chromosme mutation?

Answer 9

Duplication: changes the size of chromosomes and results in multiple copies of a single gene

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

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

Question 10

Types of Human Genetic Disorders

Answer 10

Autosomal Recessive Disorders
Autosomal Dominant Disorders
Sex-Linked Disorders
Autosomal Chromosome Disorders
Sex Chromosome Disorders

Question 11

Autosomal Recessive Disorders

Answer 11

Caused by the presence of 2 recessive alleles on autosomes

Question 12

Autosomal Dominant Disorders

Answer 12

Caused by the presence of at least 1 dominant allele on autosomes

Question 13

Sex-Linked Disorders

Answer 13

Caused by the presence of an allele on the X sex chromosome

Question 14

Autosomal Chromosome Disorders

Answer 14

Often caused by nondisjunction of autosomes = the failure to separate homologous chromosomes during meiosis.

Question 15

Sex Chromosome Disorders

Answer 15

Often caused by nondisjunction of sex chromosomes

Question 16

Pedigree

Answer 16

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

Question 17

Autosomal Recessive

Answer 17

1)Most common inheritance pattern for genetic diseases
2)Disease is rare in the family (only a few affected family members)
3)Males and females are equally likely to inherit this disease
4 )Disease often skips generations

Question 18

Autosomal Dominant

Answer 18

1 )Disease is common in the family (many affected family members)
2)Males and females are equally likely to inherit this disease.
3)Disease will never skip a generation – a child cannot inherit the disease if both parents are healthy!

Question 19

Sex-Linked Recessive

Answer 19

Disease is rare in the family (only a few affected family members)
Disease often skips generations
Males are more often affected than females
Affected fathers DO NOT pass on to their sons!