Genome Flashcards
What percentage of the human genome codes for proteins?
At most 3%
This indicates that the majority of the genome does not directly code for proteins.
How many genes were identified during the Genome Project?
19,600 genes
This was a result of the efforts during the Human Genome Project.
What is the function of transposons?
Sequences of DNA that can move in the genome
They are also known as mobile genetic elements and make up 50% of the human genome
What are retrotransposons?
Transposons that produce RNA, which is reverse transcribed into DNA and then inserted into the genome
They can be remnants of retroviruses.
What is the role of transposons in evolution and disease?
Movement can produce mutations and may be involved in some cancers and develop mental disorders
Some transposons produce small interfering RNAs which act to prevent transposition
*Any character that prevents transposition (e.g. methylation) would be favoured to prevent mutation
What is horizontal gene transfer?
The transfer of genetic material between organisms other than through traditional reproduction
It is widespread among prokaryotes and can lead to adaptations.
What are syncitins and their significance?
Genes that once encoded the envelope of a retrovirus, crucial for the evolution of the mammalian placenta
They are involved in controlling gene expression during pregnancy.
What is environmental DNA (eDNA)?
Extraction of sequences without an organism, mainly from soil, water, and air
It is a non-invasive technique used in conservation and ecology.
True or False: There is a single ‘human genome’.
False
There are multiple human genomes with variations among individuals.
What percentage of genetic variation exists among humans?
On average, we differ from each other by 0.1%
This represents about 3 million base pairs of difference.
What adaptation has been observed in the Bajau people of Southeast Asia?
Selection on PDE10A gene leading to larger spleens, acting as a reservoir of red blood cells
This adaptation is linked to their ability to dive for long periods.
How many groups of genes are necessary to be classified as an animal?
25 groups of genes
These include homeobox developmental genes, signaling pathways, and cell adhesion molecules.
What is the significance of the EPAS1 gene in Tibetans?
Controls red blood cell production; mutation found in 87% of Tibetans
This adaptation helps them survive in high-altitude environments with less oxygen.
Fill in the blank: Skin colour involves at least ______ genes.
15 genes
The genetics of skin colour is complex with substantial variation particularly in Africa.
What is the implication of the study on giraffe species conducted in 2016?
Identified four species of giraffes based on genetic sequencing
This study challenged previous assumptions based on morphology.
