![Pearson eText Genetic Analysis: An Integrated Approach -- Instant Access (Pearson+)](https://www.bartleby.com/isbn_cover_images/9780135564172/9780135564172_largeCoverImage.gif)
Concept explainers
Why might mitochondrial, Y chromosome, and autosomal DNA provide different perspectives on our evolutionary past
![Check Mark](/static/check-mark.png)
To analyze:
The reason for the relationship of mitochondria, Y chromosome, and autosomal DNA with different aspects of our evolutionary past, for example regarding our relationship with Neandertals.
Introduction:
The evolutionary relationships of closely related organisms show different evolutionary processes in a relatively short time that has been of interest to a biologist since a long time. The comparative study of phylogenies concluded from the DNA sequences with different inheritance patterns i.e. mitochondrial, autosomal, and X & Y chromosomal loci delivers best widespread conclusions of the evolutionary history.
Explanation of Solution
Mitochondria DNA: The first genetic evidence for an African origin of modern humans was analyzed from the study of mitochondrial DNA (mtDNA) polymorphism. The mtDNA specifically gives the genealogical history and evolutionary relationship of mammalian species.
The mtDNA are inherited maternally; they do not show any recombination of alleles; unlike the nuclear genome, some non-coding mtDNA can evolve quickly which leads to a variation in the mtDNA within closely related species. In mammals, the rate of mutation in mtDNA is higher than nuclear genomes i.e.
The regions around the Great Rift Valley of East Africa have been home to humans and hominin ancestors for at least 4 million years. The model of Human evolution called as RAO model (for recent African origin) proposes humans are evolved from a small African population. The RAO model suggests that modern humans arose approximately
Y chromosome: The Y chromosome sequence variation provides complementary mtDNA analysis. Y chromosome is strictly paternally inherited, and outside the pseudo-autosomal region, it does not show any recombination with other chromosomes. Y chromosome sequence is poor and provides very less sequence diversity. It has short tandem repeats (Y-STR) that can mutate rapidly about
According to the RAO model, more diversity is observed within African Y chromosome sequence than non-African sequences. As the mtDNA and Y chromosomes are strictly maternal and paternal, their haplotypes can be used to trace the migration patterns.
Autosomal DNA: The analysis of thousands of human genome sequences demonstrated that autosomal genetic diversity in African population is greater compared to the non-African population. Likewise, the study of Single nucleotide polymorphic DNA of worldwide sample population revealed the highest frequency of unique alleles in Africans compared to Non- Africans.
From all of these aspects, the mtDNA of Neandertals is different from the modern human, and it also does not show any inbreeding. The comparative nuclear genome sequences revealed that
The hybridization of Neandertals genome with modern human genome revealed that inbreeding took place after the migration of modern humans out of Africa. The other analysis also revealed that Neandertal DNA is unevenly distributed in the human genome; for example, no Neandertal DNA on the X chromosome, rather on autosomes, carries Neandertal DNA with precise distribution.
The comparative study of phylogenies concluded from the DNA sequences with different inheritance patterns i.e. mitochondrial, autosomal, and X & Y chromosomal loci, delivers best widespread conclusions of the evolutionary history.
Want to see more full solutions like this?
Chapter D Solutions
Pearson eText Genetic Analysis: An Integrated Approach -- Instant Access (Pearson+)
- How could researchers have determined that the rhesus monkeys Mito and Tracker (see Fig. 15.19) weredevoid of the mitochondrial DNA from their nucleardonor mother?arrow_forwardThe four chromosomes depicted here are Y chromosomes from men in different parts of the world. The light purple bands represent specific genesthat are identical in all four men. The red bands represent genetic mutations (M) that appeared at different times; M168 appeared about 50,000 years ago, M9 about 40,000 years ago, and M3 about 10,000 years ago. Based on whatyou have learned in this chapter, identify the geographic source of men carrying each of these chromosomes: African, Eurasian, Amerindian, and first migrants out of Africa.arrow_forwardCan you answer all the parts to this diagram Species 1 and 2 are sister species from which you’ve cloned related genes. On the gene tree on the top of the next page, use labels to answer the following questions: (a) Label the node that represents a gene duplication with “D,” (b) Label the nodes that represent speciation events with “S,” (c) Pick a pair of genes that are paralogs and label them both “P.” (d) Pick a pair of genes that are orthologs and label them both “O.”arrow_forward
- Imagine that Species A and Species B are closely related species. Species A has one hemoglobin gene, located on chromosome 5. Species B has two hemoglobin genes, one located on chromosome 5 and one located on chromosome 8. Based solely on this information, it is possible that the ancestor of Species A and Species B had one hemoglobin gene, and that a large-segment duplication followed by a translocation resulted in the second hemoglobin gene of Species B. True Falsearrow_forwardTwo diploid species of closely related frogs, which we will callspecies A and species B, were analyzed with regard to the genesthat encode an enzyme called hexokinase. Species A has two distinctcopies of this gene: A1 and A2. In other words, this diploidspecies is A1A1 A2A2. Species B has three copies of the hexokinasegene, which we will call B1, B2, and B3. A diploid individualof species B would be B1B1 B2B2 B3B3. These hexokinase genesfrom the two species were subjected to DNA sequencing, and thepercentage of sequence identity was compared among these genes.The results are shown here. Percentage of DNA Sequence Identity A1 A2 B1 B2 B3A1 100 62 54 94 53A2 62 100 91 49 92B1 54 91 100 67 90B2 94 49 67 100 64B3 53 92 90 64 100…arrow_forwardWhich of the following statements best explains the importance of sister taxa for understanding the evolution of ingroup taxa? A) The sister group informs of the likely state of the common ancestor of the ingroup. B) The sister group is composed only of ancestral characters representing a primitive taxon having ancestral states for all characters able to be studied. C) The sister group allows us to infer character state polarity in order to understand how character states have changed during evolution of the ingroup. D) A & B E) A& C F) All of the above.arrow_forward
- As we focused on linkage,chromosomal mapping, and many associated phenomena.In the pIn this chapter, we focused on linkage,chromosomal mapping, and many associated phenomena.In the process, we found many opportunities to consider themethods and reasoning by which much of this informationwas acquired. From the explanations given in the chapter,what answers would you propose to the following fundamentalquestionrocess, we found many opportunities to consider themethods and reasoning by which much of this informationwas acquired. From the explanations given in the chapter,what answers would you propose to the following fundamentalquestion ? How do we know that crossing over results from a physicalexchange between chromatids?arrow_forwardThe theory of the endosymbiotic origin of mitochondria and chloroplasts was first proposed by the biologist Lynn Which of the following statements provides support for the theory of endosymbiosis? 1. All the genes found in chloroplasts are homologous to genes found in the nucleus of eukaryotic cell. 2. Mitochondria contain their own ribosomes. 3. Proteins need a targeting sequence to be imported into a chloroplast. 4. Mitochondria can generate a proton gradient and harness it to synthesize ATP. O A. 1, 2 and 3 B. 1 and 3 C. 2 and 4 D. 4 only E. All of 1, 2, 3 and 4 are correct.arrow_forwardCharles Darwin’s claim, that the species level of classification is just as arbitrary as that of any other taxonomic level, is supported by all of the following observational failures except: the inability of a cloning species lacking biparental reproduction to interbreed with a different species the inability of an asexual eukaryotic species to interbreed with a different species the inability of a sexually-reproducing eukaryotic species to interbreed with a different species the inability of a prokaryotic species to interbreed with a different species the inability of an extinct species (like a dinosaur) to interbreed with a different speciesarrow_forward
- need helparrow_forwardWhich one of the following options most accurately describes how the ~3000 megabases (Mb; ~3,000,000,000 nucleotides) of the haploid human genome are distributed on chromosomes? The haploid human genome is distributed on autosomes 1-22 and X and Y (so, 24 chromosomes). The haploid human genome is distributed on the homologous pairs of autosomes 1-22 and X and Y (so, 46 chromosomes). The haploid human genome is distributed on a single chromosome (so, 1 chromosome). The haploid human genome is distributed on one pair of homologous chromosomes (so, 2 chromosomes).arrow_forwardIn sexually reproducing species, each individual begins life with DNA inherited from both parent organisms. , Apply this idea to what occurs when organisms of two species that have homologous chromosomes mate and produce ( F1 ) hybrid offspring. What percentage of the DNA in the F1 hybrids' chromosomes comes from each parent species? As the hybrids mate and produce F2 and later-generation hybrid offspring, describe how recombination and natural selection may affect whether the DNA in hybrid chromosomes is derived from one parent species or the other.arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage LearningBiology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage Learning
![Text book image](https://www.bartleby.com/isbn_cover_images/9781305251052/9781305251052_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781305389892/9781305389892_smallCoverImage.gif)