Genetics Unit Review Flashcards
How many autosomes does a human somatic cell contain? How many autosomes does a human gamete contain?
44 (diploid + excludes sex chromosomes)
22
How many pairs of homologous chromosomes does a human somatic cell contain? How many chromosomes does a human somatic cell contain?
23
46
The diploid number of chromosomes for shrimp is 254. How many more chromosomes does a shrimp somatic cell have than a human somatic cell?
208 (254-46)
What did X-ray crystallography reveal to
Rosalind Franklin about the structure of
DNA?
uses X-rays to determine the geometry or arrangement of atoms in a molecule
-Franklin determined that DNA had the form of a
spiral, or helix
Use a diagram to illustrate James Watson and
Francis Crick’s model of a DNA molecule
regular DNA packaging diagram (4.5 pg 98)
What is meant by “base pairing” when referring
to a DNA double helix?
The two helical strands are connected through interactions between pairs of nucleotides, also called base pairs.
Two types of base pairing occur: nucleotide A pairs with T, and nucleotide C pairs with G
What is the cell cycle?
A cell cycle is a series of events that takes place in a cell as it grows and divides.
Meiosis I vs. meiosis II
Genetic reassortment occurs during meiosis I. The first meiotic stage is also an example of reductional division, wherein a change in ploidy takes place as a diploid parent cell forms haploid daughter cells. Meiosis II, being an equational division, does not feature a change in ploidy; it instead produces haploid daughter cells from haploid parent cells. Meiosis I, also produces cells in which the chromosomes are still whole and are composed of two chromatids; on the other hand, the separation of sister chromatids occurs in meiosis II.
Meiosis II is generally regarded as being very similar to mitosis, except for the presence of two parent cells, instead of only one. In both meiosis I and II, cytokinesis occurs, and there are two daughter cells per parent cell.
Which type of chromosomal damage might
affect more than one chromosome? Explain.
In a translocation, a segment from one chromosome is transferred to a nonhomologous chromosome or to a new site on the same chromosome.
Translocations place genes in new linkage relationships and generate chromosomes without normal pairing partners
What is the term for an allele that is not
expressed in the phenotype of a heterozygous
individual?
recessive allele
How is the concept of probability applied when examining genetic crosses?
One probability rule that’s very useful in genetics is the product rule, which states that the probability of two (or more) independent events occurring together can be calculated by multiplying the individual probabilities of the events
The principles of probability can be used to predict the outcomes of genetic crosses. The gene combinations that might result from a genetic cross can be determined by drawing a diagram known as a Punnett square
What is a hybrid (in the context of genetics)?
Give an example
Hybrids are offspring that result from crossing two true breeding varieties of the same species
E.g. Mendel produced hybrids by crossing tall-stemmed pea plants with short-stemmed pea plants
What is the term for a trait determined by
more than one gene?
Polygenic trait
-characteristic, such as height or skin colour, that is influenced by two or more genes.
-because multiple genes are involved, polygenic traits do not follow the patterns of Mendelian inheritance
List and briefly explain the four main points
in Mendel’s model of genetic inheritance
1) Genes have alternative versions (alleles)
2) For each gene, organism inherits 2 alleles from parents (both same=homoz.) (both diff=heteroz.)
3) Allele may be expressed as a trait or hidden in a heterozygous individual (dominant vs recessive)
4) Each gamete carries only 1 allele for each hereditary trait due to the separation of allele pairs when gametes form
Differentiate between the law of independent
assortment and the law of segregation.
law of segregation states that every individual possesses two alleles and only one allele is passed on to the offspring
law of independent assortment states that the inheritance of one pair of genes is independent of inheritance of another pair (doesn’t affect other genes)
What does a gene map show?
shows the locations of and distances of genes on a chromosome
Do human ABO blood type alleles show
incomplete dominance or codominance?
Explain.
The human ABO blood group system exhibits codominance. The system consists of three alleles A, B, and O. Both A and B are dominant in relation to O, and therefore blood group A can have the genotype AA or AO. Blood group B can have the genotype BB or BO.
-both alleles expressed at same time… no intermediate phenotype
Why are there more men than women with
red-green colour blindness?
- x-linked recessive disorder
- males are hemizygous(X Y)= more likely to get it
(needs 1 recessive allele) - females = very rare (need 2 recessive alleles)
What is the name for the initiative to determine
the nucleotide sequence of all human
chromosomes?
Human Genome Project
What are some ways to identify genes in DNA
sequences?
- Automated DNA sequencing machines (a computer
is given instructions for finding genes in the sequence
and is then left to find them) - Fluorescent dyes (nucleotides labelled with diff.
colours)
How has the ability to label nucleotides with
fluorescent dyes benefited genetic research?
can be used to rapidly and accurately sequence a DNA template in a DNA polymerase reaction
What are some features of plasmids that make
them useful in genetic engineering?
amplify, or produce many copies of certain genes
What is a DNA chip?
small glass wafer or slide spotted with an array of single-stranded DNA fragments
-some spots (for example) could contain DNA with mutations known to cause cystic fibrosis
Give one application for a transgenic plant
and one for a transgenic animal.
GM plants are used in biotechnology for the production of pharmaceuticals, industrial products, or biofuels (renewable fuels from plant matter or other
organic materials). For example, genetic engineers have developed lines of safflower plants that produce a wide variety of products. One of these products is insulin, for the treatment of diabetes. Transgenic
safflower can efficiently produce authentic molecules of human insulin
goal is to make a transgenic animal that produces a large amount of a rare biological substance for medical use. Using transgenic animals to produce pharmaceuticals is sometimes called “pharming.” Most cases involve adding a gene for a desired human protein, such as a hormone, to the genome of a farm mammal
Give two reasons for determining the nucleotide sequence of a gene
-tells scientists the kind of genetic information that is carried in a particular DNA segment
-blueprint that contains the instructions for building an organism, and no understanding of genetic function or evolution could be complete without obtaining it
Was Dolly the sheep a transgenic organism?
Explain
She was cloned with a genetically modified cell using somatic cell nuclear transfer (SCNT).
This was the method used to produce Dolly the Sheep, although she was not genetically modified as she was created using an unmodified cell. (nuclear transplantation)
transgenic: acquired 1 or more genes from a different type of organism
List two difficulties with using somatic cells
to clone animals
many embryos do not survive, and the clones
can have serious health problems
What is the main difference between taking
a pharmaceutical, such as an antibiotic, and
undergoing gene therapy?
Antibiotics are medications that destroy or slow down the growth of bacteria. They include a range of powerful drugs used to treat diseases caused by bacteria.
Gene therapy replaces a faulty gene or adds a new gene in an attempt to cure disease or improve your body’s ability to fight disease. Gene therapy holds promise for treating a wide range of diseases, such as cancer, cystic fibrosis, heart disease, diabetes, hemophilia and AIDS
What is the term for a line of mice with a
gene that has been altered so that it no
longer functions?
Knock-out mice
-transgenic mice used in medical research
-genome is altered in knockout mice so that a gene no longer functions (the gene is “knocked out”).
Why is it important for cells to have a control
system that regulates cell division? Describe a
possible consequence of a malfunction in cell
cycle control
Disruption of normal regulation of the cell cycle can lead to diseases such as cancer. When the cell cycle proceeds without control, cells can divide without order and accumulate genetic errors that can lead to a cancerous tumor
Why would undergoing meiosis be a problem
for an organism that reproduces asexually?
it would make the cells haploid instead of diploid and daughter cells would have half the number of chromosomes/DNA as parent cells
In which phase of the cell cycle would most of
your somatic cells be at any particular time?
Explain your reasoning
Interphase - 90% of time
A cell spends most of its time in what is called interphase, and during this time it grows, replicates its chromosomes, and prepares for cell division.
Predict what would happen if spindle fibres
were disrupted during anaphase of mitosis.
One daughter cell would be missing their DNA and the other daughter cell would have double the amount of DNA in their cell
the chromosomes would also fail to segregate naturally. The spindle fibers are involved in the movement and positioning of chromosomes during cell division.
=non-disjunction in mitosis
Describe how crossing over during meiosis
recombines the genetic material of an
individual organism’s two parents
During meiosis, homologous chromosomes (1 from each parent) pair along their lengths. The chromosomes cross over at points called chiasma. At each chiasma, the chromosomes break and rejoin, trading some of their genes. This recombination results in genetic variation
Explain how the assortment of chromosomes
during meiosis contributes to variation in
the gametes
When cells divide during meiosis, homologous chromosomes are randomly distributed to daughter cells, and different chromosomes segregate independently of each other. This called is called independent assortment. It results in gametes that have unique combinations of chromosomes
Use diagrams to illustrate the four main types
of large-scale mutations in chromosomes
Deletions, Translocations, Duplications and Inversions
Is it possible for a mutation to be beneficial to
an organism? Explain
Beneficial mutations are essential for evolution to occur. They increase an organism’s chances of surviving or reproducing, so they are likely to become more common over time. There are several well-known examples of beneficial mutations. Here are just two:
Mutations in many bacteria that allow them to survive in the presence of antibiotic drugs. The mutations lead to antibiotic-resistant strains of bacteria.
A unique mutation is found in people in a small town in Italy. The mutation protects them from developing atherosclerosis, which is the dangerous buildup of fatty materials in blood vessels.
If DNA damage occurs in G1 phase, what
might happen to the damaged region during
S phase?
-it won’t replicate or the damaged DNA will replicate
Contrast the possible impacts of a chromosomal
mutation that occurs in meiosis to one that
occurs in mitosis in a somatic cell
meiosis:
-result in changes in the number of chromosomes in a cell or changes in the structure of a chromosome
-chromosome mutations change and impact the entire chromosome
-examples of conditions that result from abnormal chromosome numbers are Down syndrome and Turner syndrome.
mitosis:
-not passed on to children
-can (but do not always) cause cancer or other diseases
-production of daughter cells with too many or too few chromosomes, a feature known as aneuploidy.
-nearly all aneuploidies that arise due to mistakes in meiosis are lethal
-can be any genomic variation: repeats, deletions, insertions, multiplication, loss of copy number, and others
-chromosomal somatic mutations occur when somatic cells divide
How might a biologist use a karyotype to
identify a species?
Karyotypes can be used to identify a species because different species have different numbers of chromosomes. Humans have 46 chromosomes, while mallards have 80 and fruit flies have only eight. This applies to the species of any type of organism.
In a human, how many pairs of chromosomes would there actually be at the start of meiosis I?
23
Give three reasons that fruit flies are useful
model organisms for genetic research
75% of the genes that cause disease in humans are also found in the fruit fly.
Drosophila have a short, simple reproduction cycle. It is normally about 8-14 days, depending on the environmental temperature. This means that several generations can be observed in a matter of months
It is relatively straightforward to mutate (disrupt or alter) fruit fly genes.
What evidence from Gregor Mendel’s
experiments showed that alleles assort
randomly in meiosis?
When an organism makes gametes, each gamete receives just one gene copy, which is selected randomly. This is known as the law of segregation
pea plants with two different traits produced offspring that all expressed the dominant trait, but the following generation expressed the dominant and recessive traits in a 3:1 ratio.
Sexually reproducing organisms use mitosis
and meiosis, while asexual organisms use only
mitosis. Which type of reproduction, asexual
or sexual, results in offspring with a greater
variation? Explain
Sexual reproduction provides genetic diversity because the sperm and egg that are produced contain different combinations of genes than the parent organisms.
Asexual reproduction, on the other hand, does not need sperm and eggs since one organism splits into two organisms that have the same combination of genes(genetically identical)
Some genes for animal coat colour or feather colour are expressed differently depending on body temperature or season. How might this phenomenon benefit an animal in the wild?
Camouflage, also called cryptic coloration, is a defense or tactic that organisms use to disguise their appearance, usually to blend in with their surroundings. Organisms use camouflage to mask their location, identity, and movement. This allows prey to avoid predators, and for predators to sneak up on prey
Why would it be important for an animal
breeder to know the genotype of an animal
and not only its phenotype?
Bc genotype is the set of genes that determine a phenotypic trait within an animal
Is it likely that the human Y chromosome
contains any genes necessary for survival?
Explain
Although it carries the “master switch” gene, SRY, that determines whether an embryo will develop as male (XY) or female (XX), it contains very few other genes and is the only chromosome not necessary for life
The effects of a particular mutation may
not always be visible. How might a researcher
determine if a mutation has occurred in
a gene?
GFP
Biologists use GFP as a marker protein. GFP can attach to and mark another protein with fluorescence, enabling scientists to see the presence of the particular protein in an organic structure. GFP refers to the gene that produces green fluorescent protein
Breeding
If an animal has a gene with the mutation, breed it(self-fertilize) and see if it appears in the F2 generation
Sequence Genome + compare it to normal gene
Explain how a model organism could be used
to help determine the effects of a mutation in
a particular gene
Both knock-out and knock-in models are ways to target a mutation to a specific gene locus. These methods are particularly useful if a single gene is shown to be the primary cause of a disease. Knock-out mice carry a gene that has been inactivated, which creates less expression and loss of function; knock-in mice are produced by inserting a transgene into an exact location where it is overexpressed
What are two things that must occur in order
for a gene therapy to be successful?
delivering a gene to the correct target and making sure the therapy works in the long term.
ensuring that the DNA and delivery methods used do not harm patients
Could a genetic counsellor use a karyotype
to identify disease caused by a small DNA
mutation? Explain
A karyotype test looks at the size, shape, and number of your chromosome… so yes
If an organism has 6 chromosomes in each cell after meiotic division, what is its diploid chromosome number?
12 (meiotic = haploid (x2))
A dog somatic cell has 78 chromosomes. How many sister chromatids will a dog cell have between S phase and metaphase I?
156 (DNA gets duplicated)
A dog somatic cell has 78 chromosomes. How many chromosomes will each new dog cell have after mitosis?
78(diploid)
What are the 2 possible gametes that could be produced by a plant with the genotype Aa? Give the probability of producing each gamete.
50% A, 50% a
List all possible allele combinations in the gametes of an individual with genotype AaBb
AB, Ab, aB, ab
The allele for cystic fibrosis is recessive. Suppose both members of a couple are heterozygous for the gene related to cystic fibrosis. What is the probability that their first child will have cystic fibrosis?
allele= recessive
Cc & Cc
=25% (punnett square)
Suppose a man has Huntington’s disease. What is the probability that one of his children will inherit the disease from him? What is the probability of that two of his children will inherit the allele from him?
50%; 25%
In Labrador retriever dogs, the allele for a black-coloured coat (B) is dominant to the allele for a chocolate-coloured coat (b). Suppose a heterozygous male is mated with a homozygous recessive female. Determine the genotypes and phenotypes of the offspring from this cross and give their proportions.
1/2 black (Bb), 1/2 chocolate (bb)
Give the phenotypes of the F1 gen from a cross between a white snapdragon and a pink snapdragon.
pink and white
Suppose an organism has the genotype AaBBCC. List all the possible allele combinations in the gametes for this individual.
ABC, aBC
The technique by which mammals are often genetically modified is by…
: injecting a plasmid with the desired gene into a fertilized egg.
Genetically modifying an animal is more difficult than genetically modifying a plant. The process of injecting a plasmid with the desired gene into a fertilized egg, then implanting the egg into a womb, is called in vitro fertilization.
Gel electrophoresis sorts…
: DNA fragments of different lengths.
Gel electrophoresis sorts DNA fragments by running an electric current through the gel that the fragments are placed in. The fragments move within the gel, and are sorted based on their lengths.
A virus can be used as a vector to insert a functional gene into a cell with a mutated gene. What is the round pink structure into which the virus injects the DNA?
Nucleus
The virus is used to deliver a functional gene into the nucleus of the targeted cell.
What best describes a restriction enzyme?
Bacterial protein
A ____________________ is a small, circular DNA molecule that is separate from the much larger bacterial chromosome.
Plasmid
Placing a recombinant plasmid into a bacterial cell to make many copies of a desired gene is called____
gene cloning
The complete collection of cloned DNA fragments from one organism is contained in a
genome
Combining genes from different sources is known as
recombinant DNA technology
Scientists often genetically modify a plant by…
infecting a cultured plant cell with a soil bacterium that contains a plasmid with the desired gene.
How is an entire animal cloned
By replacing the nucleus of an unfertilized egg
A technique that uses an electric current to separate DNA fragments is called…
gel electrophoresis
Mice can be bred with green fluorescent eyes by getting them to produce a green fluorescent protein (GFP) that they would not normally produce. Such mice are helping us to understand retinitis pigmentosa, a disease caused by a gene mutation in humans. Which is the first task involved in carrying out this research?
Fuse the mutated human gene with a jellyfish gene for GFP
Which is a specific branch of study in which researchers study model organisms, such as mice, in order to understand the functions of genes and other parts of the genome?
Functional genomics
What is the general concept of gene therapy?
A functional therapeutic gene is delivered to a particular cell or group of cells
What vector is most likely used to insert the herbicide resistance gene into the canola genome?
A plasmid from a soil bacterium
A new high-strength fibre material is made from a recombinant spider silk-like protein extracted from the milk of transgenic goats. Which technology would be best suited (most reliable and quickest) to create a large number of these valuable goats?
Animal cloning
Our genes are made of information-rich molecules called:
DNA.
A gene is a unit of information that carries a code for a certain trait or function. Genes are physical locations on DNA.
How is information stored in DNA?.
In the arrangement of nucleotides that code for genes
A diploid human cell contains
I) 46 chromosomes
II) 23 homologous chromosome pairs
III) 2 complete haploid sets of chromosomes
IV) 92 sister chromatids
I, II, III and IV
A normal human cell is referred to as diploid due to the fact that there are 23 pairs of homologous chromosomes, and each gamete produced by humans has half the necessary genetic material, called haploid, and contains one chromosome from each homologous pair. Each member of a homologous pair carrying a certain form, or allele, of each gene. This means that each human cell has 46 chromosomes, and since each chromosome appears as sister chromatids during cell division, 96 sister chromatids.
What is not a method bacteria use to increase genetic diversity in their population?
Sexual reproduction
Cystic fibrosis causes progressive disability, and often early death. It is caused by a single mutation in a gene that helps create sweat, digestive juices and mucus. Which technology is best suited to treat this disease?
gene therapy
A biotechnology company is attempting to synthesize the chemical alpha 1-antitrypsin, produced naturally in most humans, in sheep milk. Alpha 1-antitrypsin can be used to treat the disease cystic fibrosis. Which technology is this company LEAST likely to require in this process?
Cross fertilization:
Biotechnology companies will frequently use in vitro fertilization, recombinant DNA technology, and DNA sequencing to allow one type of cell to produce a compound, or perform a function, that is normally done in another type of cell, or even in a different species. Cross fertilization, on the other hand, is a simple technique for studying genetic traits, or for increasing genetic diversity in a species.
What is the best description of the law of segregation?
Correct Answer:
Two alleles for a trait or gene separate during meiosis Gregor Mendel’s first law of genetics is known as the law of segregation. This law states that traits are found on identical locations on homologous chromosomes, and that the two alleles for the trait (one on each of the pair) separate during meiosis. Thus, each gamete produced carries one allele or the other
The OncoMouse is a type of laboratory mouse that has been genetically modified to carry a specific mutated human gene called an activated oncogene. This gene greatly increases the mouse’s susceptibility to cancer and so makes the mouse a valuable cancer research tool. What term best describes the OncoMouse?
Transgenic
Genes are located at specific positions on chromosomes and the segregation and assortment of these chromosomes during meiosis is responsible for inheritance patterns. This statement best describes which theory, model, or law?
Chromosome theory of inheritance
If a dihybrid cross results in a ratio of genotypes that is quite different from the expected 9:3:3:1 ratio of genotypes, what is the most likely cause?
Genetic linkage
Dihybrid crosses, such as though done by Mendel, show very predictable patterns based on the chance associated with independent assortment. However, if two genes are located together on the same chromosome, they will not sort independently of each other. This is called genetic linkage. The result will be a genotypic and phenotypic ratio that may be quite different than what is expected.
Special cells that line the stomach, called parietal cells, produce and release gastric acid. Gastric acid is a chemical that is used to digest food. This is what parietal cells look like under the microscope. Parietal cells are short-lived and must divide often to replenish the stomach lining. During which phase in the parietal cell cycle is gastric acid produced and secreted?
Interphase
The cell cycle is the term used to describe the normal life cycle of a cell. Parietal cells, and other short-lived cells, will reproduce often during the mitotic phase of the cell cycle. The normal functioning of any cell, which in the case of the parietal cells is secreting gastric acid into the stomach, is done during the interphase portion of the cell cycle.
This is a diagram of a cell during division. The cytoplasm is being divided in two. What is this process called?
cytokinesis
If T stands for the dominant tall allele and t stands for the recessive short allele, then what are the genotypes of the four pea plants(3/4 tall + 1/4 short) resulting from self-fertilization (“F2” generation)?
TT, Tt, Tt and tt
In the diagram, the F2 generation (labeled here as the unknown Z) are the offspring of the cross between two heterozygous tall plants from the F1 generation with the genotype Tt. We know this because if the P generation were true-breeding, and each form of the trait was present. Therefore, the F2 generation must consist of one tall plant with the genotype TT, two tall plants with the genotypes, Tt, and one short plant with the genotype tt.
The fur colouration of this Tonkinese cat is a blend of the colourations seen in either parent. Which type of inheritance is this
Incomplete dominance
Offspring that are heterozygous for a particular trait sometimes express the trait through an inheritance pattern called incomplete dominance. This results in the heterozygous offspring exhibiting a phenotype that is a blend of the parental phenotypes; a red parent and a white parent would produce pink offspring, for example.
Which statements about the information in this table are true?
I) IA and IB alleles must be codominant
II) The i allele must be recessive
III) The blood phenotypes for IAIA and IAi are identical
IV) People with type AB blood could receive a blood infusion from any other blood type
all
The location of this allele was most likely determined using which technology?
gene mapping
Tasha, the boxer shown here, serves as the subject of the Canine Genome Project. If the entire genome of Tasha was compared with the genome of a dachshund (same species but different breed), in what way would you expect their DNA to differ?
The gene’s alleles
Seedless watermelon fruits are produced on triploid plants where meiosis is prevented and fertile gametes cannot form. In what ways would you expect the DNA to differ between a diploid plant and a triploid plant, both of an identical strain and species?
The number of genes and the number of chromosomes
Triploidy is a term used to describe organisms with three sets of chromosomes, instead of the more common two sets.
Analyze the human karyotype below. Identify
the name for this type of karyotype and the sex
of the individual. Describe the effects of the
condition associated with this karyotype(trisomy 18)
Edwards syndrome
-small heads w prominent backs (occipital bone)
-scalp lesions
-severe intellectual disabilities
-low birth weight
-small jaw + mouth
-clenched fists + clubfeet
-webbing possible
Why is an understanding of meiosis helpful in explaining inheritance patterns?
Meiosis and inheritance are closely intertwined, as parental germ cells undergo meiosis and produce gametes that carry specific alleles, and two gametes unite during fertilization to form an offspring
While in mitosis, genes are generally transferred faithfully from one cellular generation to the next; in meiosis and subsequent sexual reproduction, genes get mixed up. Sexual reproduction actually expands the variety created by meiosis, because it combines the different varieties of parental genotypes.
How does chromosome structure support
Mendel’s ideas about pairs of inherited factors?
He deduced that genes come in pairs (homologous chromosomes) and are inherited as distinct units, one from each parent.
-the structure of chromosomes implies that you have an allele that comes from each parent and those inherited characteristics of the genotype will determine the phenotype
Independent Assortment
means that there’s no genetic linkage (loci are far enough apart + won’t get inherited together)
Law of Segregation
means non-disjunction doesn’t happen
How has the information gained from the
Human Genome Project helped to increase
our understanding of genetic inheritance?
by determining the location and sequence of every human gene, this can help us determine the gene loci of genes on homologous chromosomes and therefore will tell us if the genes will be linked and if they will get inherited together
How does cellular information pass from one
generation to another?
The genetic information that is passed on from one generation of cells to the next is carried by chromosomes and passed from generation to generation through inherited units of chemical information (genes)
where do prokaryotic cells store their DNA molecules?
in their cytoplasm
What are centrioles?
Tiny structures located in the cytoplasm of animal cells that help organize the spindle.
What is the spindle?
A fanlike microtubule structures that helps separate the chromatids
What are the major factors that determine
biological characteristics
genetic influences, brain chemistry, hormone levels, nutrition, and gender
these determine how an organism looks/appearance
How does IVF affect society?
alter long-held views about biological relations, kinship and the constraints of time, space, gender and genetics on procreation
can help to diagnose fertilisation problems.
Why is it so important to protect yourself from
exposure to chemicals or radiation that could
damage your DNA? How could such damage
affect future generations?
-The radiation could damage the cell’s DNA, but the DNA repairs itself.
-The radiation could prevent the DNA from replicating correctly
-increases your chances of having reproductive problems, including having a baby with a birth defect
Ways in which GM plants could improve the world’s food supply
genetic engineering can improve crop yield, resulting in greater production of the target crop.
scientists can also engineer pest-resistant crops, helping local farmers better withstand environmental challenges that might otherwise wipe out a whole season of produce
decreases pesticide use
How might studies of genetic linkage help in
disease research?
helps determine whether the disease phenotype is only caused by mutation in a single gene or mutations in other genes can give rise to an identical or similar phenotype.
Difference between genetic recombination and crossing over
recombination is the production of different combinations of alleles in the offspring whereas crossing over is the exchange of genetic material between non-sister chromatids, the event which produces recombination
Test cross
genetic cross to determine genotype by breeding an individual of unknown genotype with a homozygous recessive individual
Non-Disjunction
Meiotic spindle makes an error in distribution of chromosomes
When homologous chromosomes do not separate during anaphase I or II
Results in gametes with either too many or too few chromosomes
If abnormal gamete unites with a normal gamete the result is a zygote that contains an atypical number of chromosomes
True or false: Plasmid DNA taken up by a bacteria cell is a part of DNA sequencing
false
What special technique is used to clone an entire animal that normally reproduces sexually?
nuclear transplantation
