Chapter 1- introduction to genomics

Question 1

How many base pairs does the human genome consist of

Answer 1

3,2 x 10 9 base pairs distributed amoung 22 pairs of autosomes and 1 pair of sex chromosomes

Question 2

define a genome

Answer 2

all the genetic material of an organism. In humans there is nucleic and mitochondrial and in plants there is nucleic, mitochondrial and chloroplast

Question 3

Define genomics

Answer 3

Study of genomes

Question 4

How many protein coding genes are there in the human genome

Answer 4

about 23000

Question 5

What are the static and dynamic components of the genome

Answer 5

The static component is the one that stays constant, it is the microbiome(the bacteria within and on our bodies) and the dynamic component is the regulatory interactions which integrates the activities of individual components

Question 6

What is the phenotype equation

Answer 6

Phenotype= genotype+ environment+life history+ epigenetics(genotypexlife experiences)

Question 7

Define phenotype

Answer 7

collection of observable traits- macroscopic, eg. hair, height and microscopic eg. whether the individual has a possibility of having sickle cell anemia

Question 8

Define genotype

Answer 8

genetic constitution, your DNA sequence(both nucleic and mitochondrial)

Question 9

What is pharmacogenomics

Answer 9

The personalized prevention and treatment of diseases based on DNA sequences

Question 10

Define life history

Answer 10

The integrated total of your experiences and the physical and psychological environment in which you grew up. Physical development depends on your nutritional history and your mental development depends on your educational history and nurture you were given. As well as your in utero environment

Question 11

Define environment

Answer 11

Anything other than the gene that is being looked at, including other genes

Question 12

Epigenetic factors

Answer 12

Genotype x life experiences- Your parents might have altered the epigenetic patterns in their cells and caused “pre-differentiation” signals which might have passed on to you. Another example is that all cells, except for eggs, sperm and immune cells, have the same DNA sequence. But, different sets of genes are expressed and silenced in different parts of the body

Question 13

Does the genome determine the features of an organism

Answer 13

No, the genome constraints but does not determine the features of an organism

Question 14

What leads organisms to explore different states within their genome, provide an example

Answer 14

Different surroundings and experiences, eg. the lac operon in E-coli

Question 15

Give an example of how environmental effects have long-term effects on development

Answer 15

Exercise contributes towards your physical development, a diet rich in phenylalanine can prevent the development of phenylketonuria. Also malnutrition, disease, and injury affects your development negatively

Question 16

How have researchers measured the importance of the different factors that contribute to a phenotype

Answer 16

Controlled experiments with genetically identical organisms, in humans monozygotic twins. Scientists compare individuals with the same genes but have been exposed to different environments. Other less controlled studies include, comparisons between identical and fraternal twins or non-twin siblings with adopted children in the same family. In plants they used clones.

Question 17

What new piece of information regarding monozygotic twins changes the method used to measured the importance of the different factors that contribute to a phenotype

Answer 17

Their DNA was found to be different, due to mutations and this caused variation at the DNA level

Question 18

List the differences in genome organization in a prokaryotic cell vs. a eukaryotic cell for the following features: size, subcellular division, state of genetic material, cell division method, internal differentiation that contains DNA

Answer 18

Prokaryotic cell: 10 um, no nucleus, circular loop with a few proteins attached (nucleiod), fission, none.
Eukaryotic cell: 0.1mm, nucleus, chromosomes, mitosis or meiosis, nuclei, mitochondria, ER. golgi complex, cytoskeleton

Question 19

Name and describe the functional regions of genes

Answer 19

1.) Protein-coding regions: 3 bases code for 1 amino acid, any nucleic sequence can be translated into an amino acid sequence in 6 ways (TGA, from T or G or A= forwards and backwards). A protein-coding region will contain open reading frames in one of six reading phases. An ORF is a potential protein-coding region of about 100 bp that begins with a start codon(AUG) and ends with a stop codon( TAA, TGA, or TAG).
In prokaryotes, a gene is a contiguous region of DNA. In eukaryotes, the coding regions of genes(exons) may be interrupted by non-coding regions called introns, which must be removed to form mature mRNA that specifies the amino acid sequence of the protein.
2.) some regions are expressed as non-protein coding RNA: they will show regions of local self-complementary corresponding to hairpin loops, eg. the genes for tRNA contains the signature cloverleaf pattern
3.) other regions are targets of regulatory interactions (motifs eg. TATA)

Question 20

Is gene identification easier in prokaryotes or eukaryotes and why

Answer 20

Its easier in prokaryotes because prokaryotic genes are smaller and contain fewer genes, genes in bacteria are contiguous- they lack introns, the intergene spaces are smaller(90% of genes in E-coli are protein-coding), ribosome binding sites are conserved. Also, protein-coding genes in eukaryotes are sparsely distributed and interupted by introns. Assembling exons are a problem

Question 21

What are the 2 basic approaches to identifying genes in genomes

Answer 21

1. ) a priori methods- seek to recognize sequence patterns within expressed genes and the genes on either side of them. Protein-coding regions have distinctive patterns of codon statistics, including the absence of stop codons
2. ) ‘been there, seen that’ methods- recognize regions corresponding to previously known genes, from the similarity of their translated amino acid sequences to known proteins in other species or by matching expressed sequence tags

Question 22

List the characteristics that are useful in identifying eukaryotic genes

Answer 22

> The initial(5’) exon starts with a transcription start point, followed by a core promoter site(about 30bp upstream). It is free of in-frame stop codons and ends immediately before a GT spice signal (sometimes a non-coding exon precedes the exon that contains the initiator codon)
Internal exons are free from in-frame stop codons. They begin immediately after an AG splice signal and end before a GT splice signal
The final(3’) exon starts immediately after an AG splice signal and ends with a stop codon (sometimes a non-coding exon follows a follows the exon that contains the stop codon)
All coding regions have non-random sequence characteristics, based partly on codon usage preferences. Hexanucleotides are best when distinguishing coding from non-coding regions. Also, using a set of known genes from an organism as a reference, pattern recognition programs for gene recognition can be tuned to particular genomes

Question 23

Are the static and dynamic aspects of the human genome similar in general features to other species genomes

Answer 23

Yes

Question 24

Which 2 directions is the field of genomics progressing as genome sequencing techniques become easier

Answer 24

1. ) to determine more and more human genome sequences, especially those that are useful for research of diseases
2. ) many different species have had their genomes sequenced for at least 1 individual

Question 25

Why are the sequences of non-human genomes available publicly, but human genome sequences are not

Answer 25

It is a matter of privacy

Question 26

Why do we sequence non-human genomes

Answer 26

They reveal information about the process of evolution and they help us to understand the function of different regions in the human genome

Question 27

What is the important principle behind evolution and how does this apply to sequencing non-human genomes

Answer 27

If evolution conserves something it is essential and if it does not conserve something it is not essential. When looking at the human genome, about 98% is not protein-coding or non-coding RNA; therefore in order to understand its functions we need to compare it to other mammalian genomes. If it is conserved there must be a reason

Question 28

Give an example of how genomes of other species have a direct application to human welfare

Answer 28

The genomes of pathogens that have developed antibiotic resistance can give us clues as to what we can do to combat this and keep ahead of them

Question 29

List some of the other practical applications for sequencing non-human genomes

Answer 29

Improving agriculture and domesticated animals, biotechnological applications, the conservation of endangered species

Question 30

What is metagenomic data

Answer 30

These are sequences determined from environmental samples, without isolating individual organisms, eg. water, soil

Question 31

What are some of the clinical applications of sequencing human genomes

Answer 31

Genetic testing: prospective parents who want to find out if their carriers for cystic fibrosis; many woman test for potentially dangerous mutations in genes BRCA1, BRCA2 and PALB2, which can predispose an individual to cancer- usually carried out when family history suggests an increased risk.
Law enforcement agencies determine DNA sequences using samples from crime scenes

Question 32

Does a genome belong to a species or a single organism

Answer 32

A single organism

Question 33

Why is it essential to relate genomes to one another

Answer 33

To see life holistically and clearly

Question 34

How do we study the genomes within species

Answer 34

We study genetic variation within and among populations

Question 35

Give some examples of the applications of sequence variations in humans

Answer 35

Medicine, anthropology, to trace migration patterns, in genealogy, in personal identification to prove that someone is a parent or in a crime investigation

Question 36

Give some examples of the applications of sequence variations in other species

Answer 36

Understanding the history of these species including the domestication of animals and crop plants and guiding efforts to enhance desirable traits

Question 37

How does any two people differ in terms of their genome

Answer 37

Any two people (except identical twins) have genomic sequences that differ at 0.1% of the positions (mutations)

Question 38

What does comparing the genomes of human allow us to learn about this 0.1% variation

Answer 38

It allows us to distinguish between random components of this variation and the variation that used to characterize different populations

Question 39

Can mutations be consistent with a healthy life and one with a long lifespan

Answer 39

Yes

Question 40

What do these mutations that are consistent with a healthy life contribute to

Answer 40

Our ethnic group and individual variety

Question 41

What does the fact that mice that lack myoglobin thrive and that are more athletic than normal mice tell us about this mutation

Answer 41

That even though they suffer from a loss of a protein it is benefitting them

Question 42

Provide an example of when a species-wide loss of an ability was not considered a disease

Answer 42

When there was a loss of biosynthetic enzymes, it contributes to a list of essential nutrients eg. most animals can synthesize vitamin C, but we need it in our diet otherwise we get scurvy

Question 43

Are most mutations synonymous or non-synonymous

Answer 43

Most of them are non-synonymous and deleterious, impairing protein function and threatening disease

Question 44

Define a mutation and provide examples

Answer 44

A mutation is a change in the DNA sequence eg. deletion, substitution, insertions and translocations

Question 45

Define single-nucleotide polymorphism (SNPs)

Answer 45

It is an individual isolated base substitutions

Question 46

Other than SNPs, what are other mutations that cause other variations within species

Answer 46

Short deletions and variations in number of replicates of repetitive sequences, including variations in copy number of genes

Question 47

Variations in human genomes are the subject of several large-scale projects. How have databases contributed to this and how are they growing

Answer 47

Databases now contain over 100000 mutations in 3700 genes. This is 6.2% of the total 23000 genes. This number is growing rapidly and about 10000 new mutations are discovered each year

Question 48

How are SNPs inherited

Answer 48

Everyone has an accumulated collection of SNPs that has been inherited from their ancestors, some are inherited as blocks, other are not

Question 49

What happens to mutations in different DNA molecules of diploid chromosomes vs. mutations on the same chromosome in terms of how they are separated

Answer 49

Mutations that occur in different DNA molecules in diploid chromosomes become separated during independent assortment in 1 generation and mutations that occur on the same chromosomes become separated more slowly during recombination.

Question 50

When do mutations in sequences remain together

Answer 50

Haploid sequences, such as most of the Y chromosome or mitochondrial DNA do not go through recombination

Question 51

By what mechanisms can mutations affect human health

Answer 51

> Some mutations destroy the activity of a protein, eg. haemophilia (blood does not clot properly) arise from a mutation in the blood coagulation cascade either factor VIII or IX. Another example is phenylketonuria (build up of phenylalanine in the body) arises from a mutation in phenylalanine hydroxylase, the enzyme that converts phenylalanine to tyrosine
Some mutations cause disease only in combination with unusual features of the environment or specific triggering events, eg. the Z-mutation of alpha1-antitrypsin (Gly342 to Lys) creates a predisposition to certain diseases due to lung damage and smoking aggravates the mutation
Loss-of-function mutations are usually recessive, so the homozygosity for the mutation has more severe consequences than heterozygosity
Many diseases are associated with the formation of insoluble aggregates, usually of misfolded proteins e.g. classical amyloidoses (build up of amyloids in organs), Alzheimers and huntingtons disease, aggregates of misfolded alpha1-antitrypsin and prion diseases (A prion is a type of protein that can trigger normal proteins in the brain to fold abnormally- a family of progressive neurodegenerative diseases)

Question 52

How does the polymerization of insulin affect diabetes therapy

Answer 52

It creates problems in production, storage and delivery in diabetes therapy

Question 53

How do mutations that destabilize proteins affect the proportion of misfolded proteins

Answer 53

It can increase the proportion of misfolded proteins and this causes them to show a greater tendency to form aggregates

Question 54

Give an example of when a mutation produced a defective protein that resulted in a beneficial trait, so it remained in populations

Answer 54

The genes for sickle-cell disease and for glucose-6-phosphate dehydrogenase deficiency provide resistance to malaria

Question 55

Can the dysfunction of a regulatory protein or receptor cause the operation of a pathway to disorganize even if all the components of the pathway are normal

Answer 55

Yes

Question 56

What are some of the effects of when an abnormal regulatory protein cannot be activated or when it is constantly activated and cannot be shut off

Answer 56

These mutations can produce:
> physiological defects: a number of diseases are associated mutations in G protein-coupled receptors. Some mutations in opsins are associated with colour blindness. Certain mutations in the G protein target the olfactory receptors lead to loss of sense of smell
> developmental defects: several types are traceable to hormone receptors, eg. Laron syndrome- a mutation in the human growth hormone receptor that results in a diminished stature. If the person receives growth hormone externally it will not help them grow

Question 57

What is the difference between the mutation in a healthy cell and a cancer cell

Answer 57

Healthy cells accumulate mutations at a moderate rate, while cancer cells accumulate mutations at an increased rate because they have lost checks on accuracy of DNA replication

Question 58

What is the best way to distinguish variations arising from the cancer cells itself from healthy cells (in research)

Answer 58

Compare sequences from tumour cells with those from normal cells from the same individual, rather than using a single reference genome

Question 59

Why do researchers sequence cancer genomes

Answer 59

To understand the origins of cancer, precise diagnosis, prognosis and therapy

Question 60

Define a haplotype

Answer 60

A group of alleles in an organism that are inherited together. It can refer to a group of alleles or to a set of SNPs found on the same chromosome

Question 61

When recombination occurs between mutations in the same chromosome how does the distance of the loci affect the frequency

Answer 61

The greater the distance the greater the frequency of recombination, but recombination rates vary widely along the genome

Question 62

During recombination what is likely to happen to SNPs located in recombination hot spots vs. cold spots

Answer 62

They are more likely to separate in hot pots and stay together in cold spots

Question 63

In humans about how long is the average region that stays in tact

Answer 63

Regions of about 100kb is length

Question 64

How many SNPs per region that stays in tact

Answer 64

An average density of 0.1% or 100 SNPs per 100kb. Very few occur .

Question 65

How do you calculate the number of possible combinations of the SNPs

Answer 65

There are a huge number of possible combinations(2 to the power 100), but many 100kb regions show about 5 SNPs. Therefore 2 to the power 5= 32 possible combinations of SNPs

Question 66

What is the significance of haplotype in research

Answer 66

It simplifies the search for genes responsible for diseases, or any genotype-phenotype correlations. The target might be one base out of 3.2x 10 to the 9- when correlating the phenotype with haplotype you look at 100kb that contain a few genes

Question 67

What is the objective of the International HapMap Project

Answer 67

It collects and curates haplotype distributions from several human populations. SNPs are its raw material from which they identify correlations among them

Question 68

Describe the phases of the project

Answer 68

Phase I- The goal was to measure the distributions of at least one SNP every 5kb across the entire human genome. Blood samples were provided by 269 individuals from 4 continents. Over 1 million SNPs of significant frequency (>5%) were documented. In addition 10 selected 500kb regions were fully sequenced from 48 samples.
Phase II and III- Extended the analysis of the samples to determine an additional 4.6 million SNPs from the same individuals

Question 69

What were the results of the International HapMap Project

Answer 69

> Most of the variations appeared in all populations that were sampled. Some of the inter-populations differences reflect different relative amounts of the same SNPs
A very few SNPs are unique to a certain population, e.g. out of > 1 million SNPs, only 11 are consistently different (in the sample studied) between all individuals of European origin and all individuals of Chinese or Japanese origin
The genomes of individuals from Japan and China are very similar, which suggests more recent common ancestry than other population pairs in the study
The X chromosome varies more between populations than any other chromosomes. This might be because males only have one X chromosome, the genes are more subject to selective pressure. Recombinations of X chromosomes can occur in females only.
Lengths of haplotype blocks vary among the different sources of samples. They tend to be shorter among populations from Africa- consistent with the idea of an African origin of the human species. The idea is that the older the populations (the larger number of generations) the greater the chance of recombination.

Question 70

What is the MHC

Answer 70

The Major Histocompatibility Complex(in humans it is known as the human leucocyte antigen[HLA]system are proteins in the human genome that are encoded in a 4 Mb region on chromosome 6.

Question 71

How are MHC proteins expressed in a species of vertebrates

Answer 71

Each individual expresses a set of MHC proteins

Question 72

Do these proteins have sequence variability, explain

Answer 72

Yes, this system is highly polymorphic- with 50-150 alleles per locus. It has a higher sequence variability than most polymorphic proteins

Question 73

How does the individual variation of the MHC region compare with other haplotype blocks

Answer 73

The set of MHC proteins expressed defines a partial haplotype of an individual and compared with other haplotype blocks the MHC region shows wide individual variation

Question 74

The MHC region contains over 120 genes coding for proteins, list the functions of these proteins

Answer 74

> provides the mechanism by which the immune system distinguishes ‘self’ molecules from foreign invaders that must be removed
determines individual profiles of competence for resistance to diseases
are useful markers for determining relationships among populations of humans and animals. Also, for tracing large-scale migrations and population interactions

Question 75

Explain how MHC haplotypes control donor-recipient compatibility in transplants

Answer 75

Surgical patients(if not immunosuppressed by drugs) will reject transplanted organs(unless the donor is an identical sibling) because the transplant is recognized as foreign. MHC proteins bond peptides and present them on cell surfaces. The triggering event in alerting the immune system to the presence of a foreign protein is the recognition by a T-cell(anti-body) receptor of a complex between an MHC protein and a peptide derived from denaturation and cleavage of the foreign protein.

Question 76

Provide another activity that MHC-peptide complexes provide in humans

Answer 76

They are involved in the removal of self-complementary T cells in the thymus during development, at the stage when the distinction between self and non-self is ‘learnt’

Question 77

How does MHC haplotype influence autoimmune diseases

Answer 77

It influences the breakdowns in self-/non-self distinguishability that result in a person’s immune system attacking his/her own tissues, eg. of autoimmune diseases include rheumatoid, arthritis, multiple sclerosis, type I diabetes and systemic lupus erythematosus

Question 78

Explain how MHC haplotypes determine patterns of disease resistance

Answer 78

Different MHC molecules have different binding specificities and can present different sets of peptides. People whose MHC molecules that do not present epitopes (the part of an antigen to which an antibody attaches to) from a certain pathogen will be susceptible to infection. Eg. MHC haplotype is a predictor of survival horizon in people infected by HIV

Question 79

Explain how MHC haplotypes influence mate selection

Answer 79

People with different haplotypes find each other romantically attractive. This mechanism is through linkage of MHC haplotype and body scent. This effect will tend to produce offspring with a larger spectrum if peptides, producing broader resistance to infection.

Question 80

Provide a short summary of MHC haplotypes

Answer 80

A person’s MHC haplotype is the set of alleles for over 100 highly polymorphic sites. MHC haplotype is a signature for individuality, it governs transplant rejection, resistance to infection and mate selection

Question 81

Define population

Answer 81

A population is an interacting and interbreeding group of individuals of the same species that inhabit the same geographical area

Question 82

When will a population display narrow variation, provide an example

Answer 82

When a population has passed through a bottleneck or that has developed in isolation from a small “founder group”, eg. cheetahs are as closely related to human siblings

Question 83

When is a population likely to have a long evolutionary history

Answer 83

When they display a high variation

Question 84

What are the two observations that make up the idea of a species

Answer 84

> many living things can be classified into discrete non-overlapping groups. These are individual species
a catalogue of these groups can be organized into a hierarchy based on their similarities

Question 85

Discuss the species concept

Answer 85

biology has a long-standing commitment to the idea of species. The species concept is based on human’s desire to organize and categorize organisms into groups for a better understanding and for research purposes. The term species appears in Darwin’s and Linneaeus’s books, but it still does not have a concrete definition. One of the reasons as to why this is, is because biology is messy and nature doesn’t work in nicely packaged boxes. Still many biologists have have worked hard to find a definition, but there are many exceptions that challenge these definitions.

Question 86

Why have many groups of higher plants and animals coalesced into a hierarchy of discrete groups, with differentiating sets of features?

Answer 86

This is because of evolution- specifically the discreteness of of the evolutionary niches for which different populations compete and the emergence of reproductive isolating mechanisms, the geographic barriers and the genomic ones.

Question 87

How does evolution generate variation in different types of organisms

Answer 87

All living things are subject to mutations. For diploid organisms independent assortment and recombination provide variation. For haploid organisms they use gene transfer to generate and propagate useful variants. For higher organisms sexual reproduction and horizontal gene transfer.

Question 88

How do eukaryotes and prokaryotes generate variation

Answer 88

Eukaryotes use sexual reproduction- they have ancestors and descendants and can be organized into
a hierarchy, while prokaryotes that exchange genetic material does not fit the classical hierarchy.

Question 89

Discuss the role of genomics in ‘species’

Answer 89

Genomics has both raised opportunities and challenges when it comes to defining species. The good thing is that DNA sequences among individuals of different species differ more than the variation that is seen among individuals of the same species. The con is that the extent of sequence diversity that distinguishes species is variable across taxa. Genomic distance(variation across the genome) does not provide a definition of species.

Question 90

How are bacterial species defined in microbiology

Answer 90

Bacterial species are defined as a set of strains that maintain > and = 97% sequence identity in the gene 16S rRNA

Question 91

Explain why we reconstruct genomes

Answer 91

They contain records of evolutionary history. The organisms on earth are the product of their response to the environment and the interactions that they have with individuals and species, for example the competition among members of the same species and the attack and defense between different species(Humans and pathogenic viruses and bacteria)

Question 92

Explain how the geological environment has been imposed by early life in the longer term

Answer 92

Early organisms released oxygen through photosynthesis, 2.5-1.9 x 10^9 years ago. This change in the composition of the atmosphere made the development of aerobic metabolism possible

Question 93

A palaeontologist named G.E Hutchinson wrote a book entitled the ecological theater and the evolutionary play, what did he emphasize

Answer 93

The interdependence of the environment and living things, which reciprocally affect each other. For example oxygen introduction

Question 94

Why will we never know the full extent of the species that nature has generated

Answer 94

The organisms alive today represent 1% of all organisms that have existed on earth

Question 95

How was the conclusion that all living organisms are related reached

Answer 95

For higher organisms their anatomy and embryology was studied and compared. For prokaryotes their biochemistry and genome were studied.

Question 96

Explain the causes of extinction

Answer 96

Darwin was the first to argue that new species arise, but Cuvier was the first to propose that species can go extinct. He believed that the extinction of species was the result of natural catastrophes. Sometimes natural catastrophes do cause extinction, eg. the asteroid that landed in what is now known as the Yucatan peninsula of Mexico, about 65 million years ago( at the boundary between the cretaceous and tertiary ages). However in other cases species become extinct because of a gradual change in the environment. It can also be the result of deliberate activity, eg. sailors killing Dodos in Mauritius or the extinction of smallpox. Today extinction occurs because of human activity- habitat destruction- and other are natural events, such as elm yellow which affects elm trees, the fungal “white-nose disease” which affects bats, devil facial tumor disease, a transmissible( by biting) cancer in Tasmanian devils. The mass extinction that is going on now is largely the result of human activity (directly and indirectly), eg. excessive hunting, habitat destruction(including the effects of climate change), the transplant of species that replace native ones and the introduction of toxic chemicals into the environment. Also, the extinction of one species can lead to the loss of another, eg. some plants are dependent on a particular insect for pollination. If that insect becomes extinct then that plant will suffer. The origin of new species and the extinction of others is a feature of the history of life.

Question 97

When is a species considered extinct

Answer 97

If no individuals has been seen in 50 years

Question 98

Provide examples of species that are extinct

Answer 98

A marsupial called thylacine or the Tasmanian wolf has been extinct since 1937 because of hunting by dogs. The Northern White Rhino, a sub-species of rhino, was functionally extinct because there were 2 females and 1 male, but the male died. However they have some of his sperm and this can be put in the female or another sub-species of Rhino to try to save them. Another example is the survival of Pere David’s deer- it occurs in china and was kept in the Emperors nature reserve, he gifted a few to zoos around Europe. The populations grew and eventually, some were introduced back into the wild.

Question 99

Can we reverse extinction

Answer 99

There are 2 proposed methods:
> selective breeding- to recover a certain species start with a closely related species that exists then choose individuals with similar phenotype and breed them over generations to produce a species similar to the extinct one, eg. for Mammoths, start with an Asian elephant, select individuals with long hair. long tusks, hump behind skull, etc. Continue after many generations. The only problem with elephants is their generation time, so you could choose species like the passenger pigeon that has a shorter generation time. The issue with the selective breeding method is even if the individuals have a similar phenotype to the extinct species they do not have the exact genotype so they cannot be the extinct species.
> Use CRISPR/Cas system to modify the genome of a living relative to approach that of the extinct species. This approach assumes that you know the genome sequence of the target species and that there is a related species to act as the host.