What are the characteristics of and differences between mitochondrial DNA (mtDNA) and Y-Chromosome DNA? What do each tell us about the origins and dispersal of modern human populations?
Mitochondrial DNA
Mitochondria are structures within cells that convert the energy from food into a form that cells can use. Each cell contains hundreds to thousands of mitochondria, which are located in the fluid that surrounds the nucleus (the cytoplasm). Although most DNA is packaged in chromosomes within the nucleus, mitochondria also have a small amount of their own DNA. This genetic material is known as mitochondrial DNA or mtDNA. In humans, mitochondrial DNA spans about 16,500 DNA building blocks (base pairs), representing a small fraction of the total DNA in cells.
Mitochondrial DNA contains 37 genes, all of which are essential for normal mitochondrial function. Thirteen of these genes provide instructions for making enzymes involved in oxidative phosphorylation. Oxidative phosphorylation is a process that uses oxygen and simple sugars to create adenosine triphosphate (ATP), the cell's main energy source. The remaining genes provide instructions for making molecules called transfer RNA (tRNA) and ribosomal RNA (rRNA), which are chemical cousins of DNA. These types of RNA help assemble protein building blocks (amino acids) into functioning proteins.
Y- Chromosome DNA
The Y chromosome is one of the two sex chromosomes in humans (the other is the X chromosome). The sex chromosomes form one of the 23 pairs of human chromosomes in each cell. The Y chromosome spans more than 59 million building blocks of DNA (base pairs) and represents almost 2 percent of the total DNA in cells.
Each person normally has one pair of sex chromosomes in each cell. The Y chromosome is present in males, who have one X and one Y chromosome, while females have two X chromosomes.
Identifying genes on each chromosome is an active area of genetic research. Because researchers use different approaches to predict the number of genes on each chromosome, the estimated number of genes varies. The Y chromosome likely contains 50 to 60 genes that provide instructions for making proteins. Because only males have the Y chromosome, the genes on this chromosome tend to be involved in male sex determination and development. Sex is determined by the SRY gene, which is responsible for the development of a fetus into a male. Other genes on the Y chromosome are important for enabling men to father biological children (male fertility).
Many genes are unique to the Y chromosome, but genes in areas known as pseudoautosomal regions are present on both sex chromosomes. As a result, men and women each have two functional copies of these genes. Many genes in the pseudoautosomal regions are essential for normal development.
Difference between Mitochondrial DNA and Y-Chromosome DNA
S.no | mitochondrial DNA | Y- Chromosome DNA |
1 | small circular chromosome found inside mitochondria | one of the two types of sex chromosome transmitted from father to son |
2 | size is 16,569bp | size is 59 million bp |
3 | consists of 37 genes | consists of over 200 genes including 72 protein coding genes |
4 | a circular covalently closed, ds DNA | occurs in a acentric and linear chromosome containing a short p-arm and a significantly long q-arm |
5 | occurs inside the mitochondria | occurs inside the nucleus |
6 | not a component of genomic DNA | a component of genomic DNA |
7 | occurs in both plants and animals | occurs in mammals |
8 | produces a single polycistronic mRNA | produces monocistronic mRNA |
9 | doesn't undergo mutation | undergoes mutation |
10 | passed along the matrilineal line | passed along the patrilineal line |
Well-resolved molecular gene trees illustrate the concept of descent with modification and exhibit the opposing processes of drift and migration, both of which influence population structure. Phylogenies of the maternally inherited mtDNA genome and the paternally inherited portion of the nonrecombining Y chromosome retain sequential records of the accumulation of genetic diversity. Although knowledge regarding the diversity of the entire human genome will be needed to completely characterize human genetic evolution, these uniparentally inherited loci are unique indicators of gender in modulating the extant population structure.
What are the characteristics of and differences between mitochondrial DNA (mtDNA) and Y-Chromosome DNA? What do...
1.Answer the following questions based on the assigned article "Human Hybrids" by Michael Hammer. a. Initial analyses of mitochondrial DNA did not find any evidence of interbreeding between Neandertals and modern humans. We now know, however, that they did interbreed. Why might these early mtDNA studies have found this confusing result? b.According to the article by Hammer, contemporary genetic analyses, showing that Neandertals and Archaic humans made at least some contribution to the modern human gene pool, favor a Hybridization...
Firstly I could do with a brief description of mitochondrial DNA. How does the structure of DNA in mitochondria compare to animal DNA (for the sake of simplicity let's say human - some animals might have unusual DNA structure) and what living organism is the mitochondrial genome most akin to? (Circular like bacteria maybe?) and are the mitochondria within a single human homogenous? Secondly, and most importantly to my aim, does the mitochondrial genome recombine in anyway? Is the process...
What is the difference between growth DISTANCE charts and growth VELOCITY charts? What do they each measure? What are some key differences between the charts (units on y-axis, at what ages is the highest point on the charts, or the lowest points, and what are their values, where are there increasing or decreasing slopes) and what do they tell us about growth?
what does the enzyme Helicase do in BOTH RNA and DNA? and what are the differences between the two?
DNA and RNA: A. One difference between RNA and DNA is the pentose sugar. What characteristics are affected by the type of sugar in the molecule? B. Why can there be unusual base pairings in RNA, but with DNA it has to be GC and AT base pairs only?
What prevents recombination between the x and the y chromosome?
What are the characteristics of a monopolistic competition? What are the differences and similarities between a monopolistic competition and a perfect completion? Give an example for each of these two market structures.
• What are 2 differences between RNA and DNA? • The suffix –ase shows that a molecule is a(n) _ • DNA template: TTA GCG GTA ATC CAT AAG CGT • becomes ... • NEW DNA: • T pairs with A • G pairs with C
Describe the four levels of protein structure. What are the similarities and differences between DNA and RNA?
DNA STRUCTURE Imagine two species, X & Y. Each species is haploid and has a single chromosome of 10,000 base pairs (bp or 10 kbp). You are analyzing their DNA, and you find that 2 kbp of species X are adenine and 4 kbp of species Y are guanine. Use this information to answer the following questions: 9. For species X, how many kbp of DNA there are for each of the four nitrogenous bases: adenine (A), thymine (T), guanine...