Term
| Who is the closest living relative to humans? |
|
Definition
|
|
Term
| How many percentages of genome are common between human and chimp? |
|
Definition
|
|
Term
| Nucleotide divergent between human and chimp is... |
|
Definition
| 1.23% (35 million single nucleotide changes). This number is inflated because some nucleotide variants are polymorphic within humans or chimps. The estimated fraction of fixed differences is≈1%. Excluding gaps! |
|
|
Term
| Nucleotide divergent between human and chimp with indels is ... |
|
Definition
|
|
Term
| How many indels differences are between human and chimp? |
|
Definition
| 5 million small (1-15 bp) indel differences between human and chimp |
|
|
Term
| What types of differences between genomes exist? |
|
Definition
| larger insertions/deletions, differences in gene or genome region copy number, differences in transposable elements, and differences in repetitive DNA |
|
|
Term
| Why the Y chromosome is the most divergent? |
|
Definition
| higher mutation rate in the male germline, because male reproductive cells undergo more cell divisions than female |
|
|
Term
| How many time do autosomes/Y/X spend in male? |
|
Definition
Autosomes - 1/2
X - 1/3
Y - 1 |
|
|
Term
| How many aas differs between protein in human and chimp? |
|
Definition
|
|
Term
| How many proteins are identical between human and chimp? |
|
Definition
|
|
Term
| How many OR genes does human have? How many functional? |
|
Definition
|
|
Term
Why OR genes are being lost rapidly in
humans? |
|
Definition
1) One might speculate that cooking leads to a reduced need to identify toxins in foods
2) Some of the OR genes that remain in the human genome show evidence for positive selection. Many unnecessary OR genes are lost and become pseudogenes, but others have evolved adaptively in humans |
|
|
Term
| What Ka/Ks ratio corresponds to negative/neutral/positive selection? |
|
Definition
Ka/Ks < 1: negative (purifying) selection
Ka/Ks = 1: no selection; completely neutral evolution
Ka/Ks > 1: positive selection
Ka/Ks is sometimes known as dN/dS or ω(omega) |
|
|
Term
| Which functional groups of genes that are enriched for positive selection? |
|
Definition
-tumor supression and apoptosis
-spermatogenesis
-sensory perception
-immune defense
-testes expressed genes
-genes on the X chromosome
same groups of genes tend to show up as positively selected in comparisons of other species |
|
|
Term
| Is any signs of positive selection for brain genes? |
|
Definition
|
|
Term
|
Definition
| humans with mutations in this have impaired speech and language skills |
|
|
Term
|
Definition
| humans with mutations in this gene have primary microcephaly = small brain (≈400cm).Normal≈1400cm |
|
|
Term
|
Definition
| mutations also cause primary microcephaly in humans |
|
|
Term
| Which genes show accelerated evolution in human? Why? |
|
Definition
| FOXP2, ASPM, microcephalin show evidence for accelerated evolution (more amino acid changes) in lineages leading to humans. Natural selection may have favoured larger brains and the ability to use language in humans. |
|
|
Term
| What was suggested as explanation for difference in human/monkey phenotype? |
|
Definition
| Many of the phenotypic differences between species may be caused by differences in gene expression. That is: when, where, and how much the genes are expressed |
|
|
Term
| Transcriptome (gene expression) of which organ appeared to evolve faster in humans?What it supports? |
|
Definition
| Brain, hypothesis that rapid evolution of the human brain was caused by changes in gene expression |
|
|
Term
| What are the results of Khaitovich, 2004? |
|
Definition
| Linear change in both brain and liver expression divergence with time – no increase of expression changes in the human brain. This is analogous to a “molecular clock” |
|
|
Term
| How the contradiction between Enard and Khaitovich, 2004 was explained? |
|
Definition
1)The first study was based on only about 5% of brain-expressed genes
2)fewer genes on chips
3)results based only on genes with expression differences between chimp and human |
|
|
Term
| What are the results of Khaitovich, 2005? |
|
Definition
genes expressed in brain evolve the slowest at both the expression and protein level. Genes
expressed in testis evolve the fastest |
|
|
Term
| What are the results of Khaitovich, 2006? |
|
Definition
When the changes are mapped onto the human or
chimp lineage, there is an excess of changes in the lineage leading to humans.1)Reduction of purifying selection in the human brain(more changes) 2)natural selection has favored gene expression and amino acid changes in the evolution of the human brain. Genes show higher linkage disequilibrium (LD)=consistent with “selective sweeps” |
|
|
Term
|
Definition
| small molecules of <1,500 Daltons that are extracted from various tissues |
|
|
Term
| Where were the biggest changes in metabolome found? |
|
Definition
| The greatest changes appear to have occurred in muscle, followed by the brain |
|
|
Term
| Why the most changes in metabolome were discovered in muscles/brain? |
|
Definition
| energy requirements of the human brain have led to a reduction in energy consumption by muscles: humans have larger brains with greater cognitive abilities, but have weaker muscles |
|
|
