5. Tischkoff et al. (1996) chose to genotype the modern human CD4 gene, specifically in terms...

5. Tischkoff et al. (1996) chose to genotype the modern human CD4 gene, specifically in terms of the length of a short tandem repeat sequence (STR) in an intron, along with a closely-linked Alu element that was partially deleted in some individuals. Define these terms and explain how their genotyping was performed. Why was the rate of mutation in these particular genetic markers expected to be appropriate for studying recent events in human evolution? Why was natural selection expected to have a minimal impact on these genetic markers? Why (how) did the results support the “out of Africa” model, both in terms of the genetic diversity of various modern human populations, and also in terms of the inferred ages of those populations?

Tishkoff, S. A. et al. (1996) Global patterns of linkage disequilibrium at the CD4 locus and modern human origins. Science 271, 1380-1387.

Expert Solution

STR or short tandem repeats are DNA sequences within intronic regions that are 2-13 nucleotides long. Alu elements are considered to be transposable elements that have millions of copy within the genome. Blood sequence from 1600 individuals spanned across different continents were taken and CD4 STRP analysis using PCR was done. CD4 STR started as a small repeat but over the course of 4-6 million years of evolution have developed a high level of mutations. Due to variation in STR lengths the sequences varied from 80 to 135 bp. Since STRP have moderate to high rates of mutation (as previously studied) The series of mutation can help a researcher to understand the level of polymorphism and human evolution.

The sequences selected are non coding regions. Linkage disequilbrium was found between Alu sequence and STRP. Genetic drift might have played a role in evolution/ variation in sequences/polymorphisms rather than process of natural selection.

An out of Africa model is one in which ancestors have evolved from Africa and moved to various places during course of evolution. Decreased variation in terms of sequence in non-African population further suggests linkage disequilibrium compared to African population. Also mitochondrial gene data also suggests the same.

gladiator answered 2 years ago

5. Haak et al. (2015) found by admixture analysis of ancient and modern human DNAs that...

5. Haak et al. (2015) found by admixture analysis of ancient and modern human DNAs that a massive wave of genetic ancestry linked to the steppes of southern Russia first appeared in Europe in the late Neolithic. Moreover, this “Russian steppe” genetic component has remained significant in most European nationalities ever since. Describe more specifically what experiments they performed, how their admixture analyses were structured, and how their results were interpreted. What were the implications of these results for the...

In the review by Eberhart et al., the authors suggest that gene-environment interactions play a pivotal...

In the review by Eberhart et al., the authors suggest that gene-environment interactions play a pivotal role in development defects. Please briefly compare and contrast in a one page, how this is similar to what happens in cancer and/or aging roles in developmental defects.

1. What specifically would happen to an individual human that lost their CD4+ T cell population?...

1. What specifically would happen to an individual human that lost their CD4+ T cell population? Provide a real-world example of this. 2. Why do infectious pathogens that evade the first and second lines of defense often cause illnesses that last for days? 3. What is the effect of cholera toxin? When in the infectious cycle does Vibrio cholerae secrete cholera toxin, and how does it know when to secrete it?

Human immunodeficiency virus (HIV) preferentially destroys CD4 T cells. Specifically, what effects does this have on...

Human immunodeficiency virus (HIV) preferentially destroys CD4 T cells. Specifically, what effects does this have on antibodies and cell-mediated immunity? Infer from your response, if you'll be more likely to develop opportunistic infections or not as a result of HIV infection.

Create a 5-step modelling process based on the work of Lankhorst et al

The human gene Trl is maternally imprinted. Hannah has a heterozygous genotype include one wildtype allele...

The human gene Trl is maternally imprinted. Hannah has a heterozygous genotype include one wildtype allele and one copy of the mutant “1” allele, Trl+Trl1. Hannah expresses the mutant allele. Describe the methylation pattern of Trl alleles in Hannah’s somatic cells and in her gametes.

Create a 5-step modelling process based on the work of Lankhorst et al (see reference reading,...

Create a 5-step modelling process based on the work of Lankhorst et al (see reference reading, chapter 5) that can be used to create an enterprise model. Pay specific attention the aspects of the purpose of modelling and at least 5 steps to follow to create the model. (20)

A study by Lefèvre et al. (2010, PLoSONE 5: e9546) investigated whether alcohol consumption affected peoples'...

A study by Lefèvre et al. (2010, PLoSONE 5: e9546) investigated whether alcohol consumption affected peoples' attractiveness to the mosquito, Anopheles gambiae, which is the primary vector for malaria in Africa. A total of 43 human participants were tested, and the attractiveness of each participant was tested twice. The first test collected a baseline attractiveness for each participant. The participants then drank either a liter of beer (n=25 participants) or a liter of water (n=18), and after 15 minutes, the...

5. Compare and contrast lumbar curvature and waist to hip ratio specifically in terms of the...

5. Compare and contrast lumbar curvature and waist to hip ratio specifically in terms of the research. Where is the research lacking? Where are there good point? (Evolutionary biology course PLZ answer it in a broad and clear way. Thank you!) Expert Answer

Question