Chapter 5: GENETIC METHODS

Question 1

What is a powerful method for estimating the influence of heredity on a particular trait?

Answer 1

-compare the concordance rate for this trait in monozygotic and dizygotic twins.

Question 2

What is the difference between concordant twins and discordant twins?

Answer 2

• If both twins are diagnosed with the same disorder, they are concordant.
• If only one is diagnosed, they are discordant.

Question 3

How can we infer that a disorder has a strong genetic basis?

Answer 3

-When the percentage of monozygotic twins who are concordant for the diagnosis is higher than that for the dizygotic twins.

Question 4

How can we use adoption to estimate the heritability of a particular behavior trait?

Answer 4

-Compare people who were adopted early in life with there biological and adoptive family members.

Question 5

How can we infer the heritability of a trait based on adoption studies?

Answer 5

-If the trait studied in the person strongly resembles traits of biological parents even if they grew apart, the trait is probably influenced by genetic factors

Question 6

What was found about the heritability of schizophrenia?

Answer 6

-Concordance rate for mono twins 4 times higher than concordance rate for dizo twins.

Question 7

What is the genome?

Answer 7

The complete set of genes that compose the DNA of a particular species.

Question 8

What is an allele?

Answer 8

-The nature of a particular sequence of base pairs of DNA that constitutes a gene; -For example: the genes that code for blue or brown iris pigment are different alleles of a particular gene.

Question 9

What is the purpose of genomic studies?

Answer 9

Determine the location in the genome of genes responsible for various physical and behavioural traits.

Question 10

What do linkage studies do?

Answer 10

Identify families whose members vary with respect to a particular trait.

Question 11

How can you infer the presence of a disease by looking at DNA?

Answer 11

A variety of markers (sequences of DNA whose locations are already known) are compared with the nature of the individual’s person’s trait.

Question 12

What do genome-wide association studies do?

Answer 12

Compare genomes of individuals to determine of genome differences correlate with the presence or absence of a trait or disease.

Question 13

What are targeted mutations?

Answer 13

Mutated genes produced in the laboratory and inserted into the chromosomes of mice.

Question 14

What are called knockout genes?

Answer 14

• Defective genes that fail to produce a new functional protein
• The target of the mutation is an enzyme that controls a particular chemical reaction.

Question 15

What are called knock-in genes?

Answer 15

-genes that produce a new functional proteins to replace a missing protein, or make increased amounts of a protein.

Question 16

What can genetic engineering be used for?

Answer 16

• Insert new genes into DNA.
• These genes can cause increased production of proteins normally found in the host species, or they can produce entirely new proteins.

Question 17

What are antisense oligonucleotides?

Answer 17

Modified strand of RNA or DNA that binds with a specific molecule of mRNA and prevents it from producing its protein.

Question 18

What role does injection of antisense oligonucleotides have in helping us to understand behavior?

Answer 18

• destroying proteins can produce changes in behavior

- this highlights the importance of proteins in behavior

Question 19

What does the CRISPR-Cas method do?

Answer 19

-technique that inactivates or alters the production of proteins by inserting new genetic sequences into DNA.

Question 20

How does CRISPR create changes in DNA?

Answer 20

• CISPR used a Cas protein to identify target sites in the double strand of DNA
• breaks both strands at that site
• cells uses one of 2 pathways to repair the DNA damage: NHEJ or HDR.

Question 21

What happens when cells use NHEJ pathway to repair DNA damage?

Answer 21

• Non-Homologous End Joining
• mutate or delete the targeted genetic sequence.
• this inactivate gene, creates a gene knockout.

Question 22

What happens when cells use HDR pathways to repair DNA damage?

Answer 22

• Homology-Directed Recombination.

- a new genetic sequence can be inserted into the cut strands of DNA.