Intro -The concept of the gene has been the focus of some hundred years of work to establish the basis of heredity, however there is no simple one line answer to the question what exactly is a gene. Genes have a variety of different functions a gene is a sequence of dna that carries information representing a protein. The sequence of dna can be identified as a continuous stretch stretch of nucleotides and chromosomes. Genes are made up of dna and act as instructions to make the molecule called proteins. Medal’s law of definition states that during production of two gametes through reproduction the two copies of each hereditary factor segregate so that offspring acquire one factor from each parent .mendal has three laws of gene types,inheritance,dominace and segregation,mendals second law summarizes the independent assortment of different genes, for example when a plant is dominant for two different characteristics is crossed with a parent that is recessive for both, for example if a human or a plant has a traits or characteristics that are recessive that means they are hidden but derived from their parents, then the recessive comes out as dominant when that human or plant reproduces offspring.
Structure of a gene- To understand a gene we must first realise the importance of chromosomes within cells. Chromosomes are responsible for are inheritance. Early experiments showed that a typical cell consists of a dense nucleus separated by a membrane from the less-dense surrounding cytoplasm within the nucleus, the granular region of chromatin. Chromosomes can be seen in most cells during the process of cell division, they are thread like structures of nucleic acids and protein found in the nucleus of most living cells carrying genetic i...
... middle of paper ...
...n as unstable alleles. Examples of this type of disease are Huntington's disease, and the myotonic form of muscular dystrophy.
Process of genetic expression-gene expression occurs throughout any organism`s life starting at the beginning, when an organism develops firstly as a zygote and later as an embryo. Genes turn on to regulate this process, cells begin exactly the same but this process changes their characteristics quickly, cells that have the ability to turn into any kind of tissue are totipotent. Cells get instructions from their dna to turn into certain kind of tissues such as skin and bone after the tissue type is decided certain genes in cells become active and others get permanently turned off. This is because gene expression is highly tissue-specific meaning certain genes are only active in certain tissues or in a particular stage of their development.
In the 19th century Gregor Mendel accomplished pioneered the first laws of genetics after crossing peas. He conducted an experiment with pea plants. He would use a paintbrush to transfer the genetic coding from one pea plant to another, so he could know exactly who the parents were. With the end of this experiment Mendel came up with two laws; Mendel 's law of segregation, and Mendel 's law of independent assortment. Mendel crossed over purple pea flowers with white pea flowers, which gave him purple pea flowers for the first generation also called F1. Since the offspring were all purple flowers Mendel understood that the purple gene was the dominant gene. Mendel decided to cross the F1 generation with themselves. Which resulted in three purple pea flowers and one white pea flower. By using basic Punnett square, and identify the genotype as PP and the phenotype as pp. This gave Mendel the following ratio of 3:1, three purple pea flowers and one
Mendel wrote that genes are passed from parents to their children and can produce the same physical characteristics as the parents.
What makes us who we are? Does the answer lie in our genes, our environment, or in the way we are raised? For years, there has been an on-going debate between nature and nurture. T.H. White, author of The Once and Future King, explores the debate through many of the book’s characters. The issue clearly appears in the relationship of Queen Morgause and her sons, the Orkney brothers. The debate caused people to pick a side, to pick nature over nurture, or nurture over nature. However, it does not have to be one or the other. Nature and nurture work together to determine who we are.
Myotonic dystrophy, type 1, is a genetic disorder which is linked to chromosome number 19 in humans. The dystrophia myotonica protein kinase gene is located on the q arm of the chromosome at the locus of 13.32. It is an autosomal dominant disorder, which means that the individuals that are affected by this disorder and contain at least one dominant allele for the dystrophia myotonica protein kinase gene. The disorder is caused by a series of repeats of a trinucleotide region that is expanded beyond the normal levels (Musova et al., 2009). The trinucleotide region is a series of repeats of CTG in the untranslated region of the dystrophia myotonica protein kinase gene. The severity of the disorder is associated with the number of repeats the individual has within the gene. Normal individuals tend to have between 5 and 37 repeats while an individual with a very mild myotonic dystrophy may have 50 to 150 repeats, and if the disorder is discovered at the time of birth the individual will have over 2,000 repeats of the trinucleotide region (Musova et al., 2009). Myotonic dystrophy, type 1, affects multiple organ systems of the body and is relatively slow to progress. Myotonic dystrophy, type 1, is categorized by alterations of the beating pattern of the heart, faulty dystrophin proteins, clouding of the lens of the eye, decreased functionality of the gonads, balding, and myotonia (Musova et al., 2009). Myotonia is described as the slow relaxation of any muscle type, which will cause the individual to use extended effort to simply relax the muscles after they have been contracted. Muscular dystrophy causes an individual to experience muscular deg...
[7] Klug, W., Cummings, M., Spencer, C., Palladino M. (2012) Concepts of Genetics: Tenth Edition. Pearson's Education, Inc.
Biologist, Gregor Johann Mendel, discovered how traits passed from one generation to the next. Mendel studied and used pea plants to discover the principles that rule heredity. He found that each parent, father, and mother pass down traits to their offspring, who inherit different combinations of their recessive or dominant alleles-terms introduced by Mendel during the 19th century. Mendel introduced important principles teaching us that recessive traits will only be shown in the phenotype if both alleles are recessive. Mendel’s laws of inheritance include the Law of segregation and the Law of independent assortment.
Eukaryotic cells have their chromosomes contained in a nucleus. Unicellular orgasisms such as amoebas and yeast, or multi-cellular organisms such as plants and animals consist of eukaryotic cells. Human being consist of approximately 1 billion cells per gram tissue. DNA located in 23 pairs of chromosomes is contained in each cell nucleus. Schleiden in 1838 and Schwann in 1839 made very important discoveries that we consist of cells, and Remark discovered that cells prolifarate through division in 1850. Three decades ago, the molecular mechanisms that regulate the cell cycle and thus cell division was able to be identified. It has been known that these vital mechanisms are conserved through evolution and function in the same way in eukaryotic organisms.
We have known for centuries that traits are passed from parents to offspring. What has not always been understood is how traits are determined. One explanation that appealed to scientist for many centuries was that traits of parents were blended, or mixed in offspring. The blending hypothesis accounted for many observable traits and was widely accepted for many years. However, the idea of blending could not account for the appearance of unexpected traits in some offspring. It was not until scientist discovered the cellular basis of life that the inheritance of traits was better understood.
The argument of nature vs. nurture is a long-standing one in the psychological and social worlds. It is the argument about whether we are ruled by our genes or our upbringing. It is my thought that neither is true. It is nature working with nurture which determines our personality and our lifestyle.
Cells are able to grow and reproduce. Cells reproduce by splitting and passing on their genes (hereditary information) to Daughter cells. The nucleus always divides before the rest of the cell divides. Therefore each daughter cell contains their own nucleus. The nucleus controls the cells activities through the genetic material DNA. The cells in a body are all the same except the gametes they were all made from one cell, the Zygote. This is the cell that was formed when two gametes from your parents fused.
Distinct characteristics are not only an end result of the DNA sequence but also of the cell’s internal system of expression orchestrated by different proteins and RNAs present at a given time. DNA encodes for many possible characteristics, but different types of RNA aided by specialized proteins sometimes with external signals express the needed genes. Control of gene expression is of vital importance for an eukaryote’s survival such as the ability of switching genes on/off in accordance with the changes in the environment (Campbell and Reece, 2008). Of a cell’s entire genome, only 15% will be expressed, and in multicellular organisms the genes active will vary according to their specialization. (Fletcher, Ivor & Winter, 2007).
The nucleus contains genetic material that controls all the activities within a cell. A nucleus is made up of D...
A genetic mutation is a permanent change in the sequence of the DNA that makes up a gene. A mutation of these sorts can be caused by either inheritance from the parent or caused sometime during the life of someone. The mutation that has been inherited is called a germline mutation. Germline mutations affect virtually the entire body, and they seem to be present in every cell. A somatic mutation, or one that is caused in the DNA of a single cell sometime during the life, can be caused by an environmental factor or a wrong bonding in the DNA molecule. These cannot be passed down to the next generation of children because they occur in a specific cell as opposed to in a reproductive cell. Some mutations occur in the embryo as it is growing. These may occur during cell division, and some of the cells may or may not inherit this mutation. Some mutations are extremely rare, and others are incredibly common. Those that occur in more than one percent across a population are considered polymorphisms. Polymorphisms are considered normal variations in DNA, and they are known to cause simple changes such as variations in blood types and hair color. Although these are not typically fatal, they can influence the creation of some disorders (Lister Hill National Center for Biomedical Communications, U.S. National Library of Medicine, National Institutes of Health, Department of Health and Human Services, USA.gov, 2013).
Genes from parents are passed down to their children and this sets up their lifelong development. When a male cell meets with female reproductive cell, they start a process for a new life in a woman’s womb. The sperm has a different copy of the gene and an egg the same and so when they meet, two copies of genes are present and through them a new life begins and it will comprise both genes. From the eyes to the color of the hair, genetics plays a role in a person’s biological make up and development. Genes can predetermine many different characteristics in human development.
Genetics is the passing of characteristics from parents to offspring through genes. Genes are information