A3.1 - diversity between organisms (5b)

Question 1

what are the observations linking complexity of organisms and relative genome size?

Answer 1

depending on the species that are compared, it may seem that organisms with larger genomes are more complex, however there are enough exceptions to conclude that a correlation is not reliable

Question 2

in what ways do the genomes from two eukaryotic species differ?

Answer 2

• genome size/number of bases/number of genes
• number of chromosomes
• base sequence/which genes are present

Question 3

What are the chromosomes values for chimpanzees and humans?

Answer 3

Humans - 46

Chimpanzees - 48

Question 4

what is the difference in the genomic variation between and within species?

Answer 4

• there is more variation between than within species
• diversity in genomes within a species is usually limited to SNP’s, whereas in eukaryotic species, there are different chromosomes that carry different genes

Question 5

what is whole genome sequencing?

Answer 5

whole genome sequencing determines the sequence of bases present in the whole genome of an organism

Question 6

what are 4 current uses of whole genome sequencing?

Answer 6

1. research into evolutionary relationships - organisms that share more similar genomes are more closely related
2. searching for genes linked to diseases
3. understanding inherited disorders
4. tracing human migration patterns

Question 7

why is whole genome sequencing more accessible than 20 years ago?

Answer 7

increasing sequencing speed and decreasing costs allows other uses of genome sequencing

Question 8

how could whole genome sequencing support personalized medicine in the future?

Answer 8

personalised medicine groups people based on their genetic profile and this can be used to predict the effectiveness of particular treatments and to apply ones that are the most effective

Question 9

what are the advantages and disadvantages of personalized medicine?

Answer 9

advantages: cost-effective and less side effects
disadvantages: security of genomic data

Question 10

what is a karyotype?

Answer 10

a karyotype is an individuals complete set of chromosomes

Question 11

what is karyotyping?

Answer 11

karyotyping is the process of using a karyogram using a karyotype where chromosomes can be collected either with:
- amniocentesis - taking amniotic fluid that surrounds the fetus
- chorionic villus sampling - taking tissue from the placenta

Question 12

what is a karyogram?

Answer 12

a karyogram is a photograph or diagram of homologous pairs of chromosomes that can be analyzed as the chromosomes are arranged in pairs based on size, banding pattern and the position of the centromere

Question 13

what types of genetic abnormalities could be analyzed using a karyogram?

Answer 13

karyograms can identify missing or extra pieces of chromosomes, or changes in chromosome numbers

Question 14

what is the hypothesis on how humans and chimpanzees have evolved to have different chromosome numbers?

Answer 14

chromosome 2 in humans arose from the fusion of chromosomes 12 and 13 with a primate ancestor shared with chimpanzees

Question 15

what evidence supports the human and chimpanzee hypothesis?

Answer 15

evidence includes:
- chromosomes 12 and 13 are the same length as chromosomes 2
- banding pattern of chromosome 2 matches that of chromosome 12 and 13
- centromere of chromosome 2 lines up with chromosome 12