Genetics and Genetic Disorders

The provided document is an assignment that delves into the realm of human genetics and genomics, covering a wide range of topics such as inherited metabolic disorders, genetic testing methods like CRISPR/Cas9, and the implications of genetic mutations. The content includes references to articles from scientific journals, providing in-depth information on various aspects of genetics and genomic disorders.

Inherited Diseases

Contents
INTRODUCTION...........................................................................................................................3
1.1 Describe the roles of DNA, mRNA, tRNA and ribosomes in protein synthesis..............3
1.2 Evaluate the effects of point mutation..............................................................................4
2.1 Explain the inheritance of phenylketoneuria....................................................................5
2.2 Describe the inheritance of gender and explain inheritance of sex-linked condition.......5
2.3 Explain the role of chromosomal abnormalities in inheritance of Down's syndrome......6
3.1 Describe process of genetic screening..............................................................................7
3.2 Describe the application of DNA recombinant technology in treatment of a named medical
condition.................................................................................................................................8
3.3 Describe moral and ethical issues raised by DNA recombinant technology....................9
REFRENCES ................................................................................................................................10

INTRODUCTION
Diseases which are caused by genetics i.e. transferred from parent’s genes to their
offerings are known as inherited diseases. It includes diabetes, haemophilia, breast cancer, sickle
cells and more, which either effect whole or a part of body due to changes in DNA ( Catalanotto,
Cogoni and Zardo, 2016). The present assignment describes concept of inherited diseases, that
includes effect of mutation on human body. Here, roles of DNA and RNA in developing protein
synthesis, inheritance of gender, role of chromosomal abnormalities and more are also explained
in brief. Furthermore, to treat the inherited diseases, procedure and importance of DNA
recombinant technology, including moral and ethical issues of same, are described.
1.1 Describe the roles of DNA, mRNA, tRNA and ribosomes in protein synthesis
DNA stands for deoxyribonucleic acid which is the genomic material, found in cells and
contains genetic information. It is mainly used in the development as well as functioning of all
parts of body that known as living organisms (Radhakrishnan and Green, 2016). DNA, RNA and
proteins, are the three main macromolecules which are essential for necessity of life. Both DNA
and RNA (ribonucleic acid) are made up of nucleosides that consider as most essential part of
protein synthesis. There, in the formation of protein synthesis, the term DNA, mRNA
(messenger RNA), tRNA (transfer RNA) and ribosomes are play an important role in living
bodies. In the process of protein synthesis, procedure is mainly divided into two major steps that
are- transcription and translation.
Here, transcription refers to a process that involves synthesis of mRNA, according to the
information on DNA’s template strand, which further helps in synthesis of protein, during
translation (Pollard and et. al., 2016). In context with Ribosomes, they are naked granules which
are found scattered within cytoplasm and made up by two subunits (one is larger and another one
is smaller). Under this process, mRNA then attached to one of its subunit in the sites of protein
synthesis, which refers to initiative step of formation of protein synthesis. As m-RNA comes out
of nucleus therefore, played a major role in protein synthesis (Devineau and et. al., 2016).
Further process is carried out by t-RNA, which are defined as small molecules that made up of

over 80 nucleotides and is mainly responsible to bring amino acids into ribosome from
cytoplasm. This transformation of amino acid results in formation of protein synthesis.
Figure 1: Structure of DNA
1.2 Evaluate the effects of point mutation
Mutation refers to changes in genetic material either by mistake or replication of DNA
molecules that results in genetic variations within a living organism (Root-Bernstein and Root-
Bernstein, 2016). For example: Sickle cell anaemia which is an inherited disease is caused due to
gene mutation. Therefore, mutation may disrupt the normal activities of body and sometime
causes diseases also such as cancer. In context with point mutation, it refers to a type of DNA or
RNA mutation under which a single unit of nucleotide either changed or deleted (Gladyshev and
Kleckner, 2016). It creates a large effect on living body and causes various type of inherited
diseases. It includes Sickle cell anaemia, Cystic Fibrosis, Tay-Sachs and more, all of which are
hardly to be cured by medical treatment procedures. Here, Cystic Fibrosis (CF) leads to a
recessive inherited disorder and generally associated with thick as well as sticky mucus in the
lungs. It affects breathing and causes salty sweat along with infertility in some individuals and
also lead to shortened life expectancy (near about 40 to 50 years). While Sickle Cell Anaemia is

a recessive disorder which is caused due to single substitution in gene. It impacts on
haemoglobin that carries out oxygen in blood. The symptoms of this disease includes anaemia,
chest pain, obstruction of blood vessels etc. and can be treated with folic acid, bone marrow
transplantation, blood transfusions and some certified prescription drugs.
2.1 Explain the inheritance of phenylketoneuria
Phenylketoneuria (PKU) refers to an inherited disorder of metabolism which causes by an
increase of a chemical in the blood. This chemical is known as phenylalanine is usually found in
all dietary products and some artificial sweeteners. It is used by body for making proteins and
helping in growth (Root-Bernstein and Root-Bernstein, 2016). But heavy intake of such food,
this chemical impact negatively on body and cause serious diseases like mental retardation, heart
problems, abnormalities and more. In general, during pregnancy women are at high risk of such
diseases for having abnormal babies like small head size, delay in development and more. PKU
is an inherited diseases that includes an autosomal recessive pattern. It reflects that an individual
has two copies of gene which is altered that causes PKU. Here, both parents of such persons
having PKU disease carries one copy of muted or altered gene but they do not show any
symptoms or sign of phenylketoneuria. Here, point mutations within PAH gene cause
phenylalanine hydroxylase that refers to low levels of an enzyme. It reflects that phenylalanine
from a diet of an individual cannot be changed or metabolized, therefore, this chemical builds up
to harmful or toxic levels within the stream of blood (Hegarty and et. al., 2015). It may cause
brain damage, heart problems and more, unless appropriate diet treatment is started.
2.2 Describe the inheritance of gender and explain inheritance of sex-linked condition
Genes are inherited from parents to their offerings where combination of different genes
that 23 pairs of chromosomes, makes every individual unique from each other. Here, genetic
inheritance controls individual's characteristics i.e. determine the sex of them either as male or
female (Lewis, 2016). Sex-linked conditions describes the different pattern of inheritance in the
autosomal forms of recessiveness and dominance, when a muted gene or an allele is present in
allosome (sex chromosome) instead of an autosome (non-sex chromosome). In human body,
there are 22 pairs present which are known as autosomes that control characteristics, while one
pair determines sex as females have two X chromosomes as XX and males inherit two different
chromosomes as XY.

In genetics theory, for testing the sex-linkage with an inheritance pattern i.e. role of
parental sex, a reciprocal cross experiment is designed. For example: To test the inheritance of
individual characteristics, where one parent had possessed altered genes then after reproduction
process, then their offerings either are affected or unaffected. One of the example of this sex
linked genes can be determined by a case study of Queen Victoria of England. She was a carrier
of altered gene i.e. haemophilia (Hernandez, Reed and Singleton, 2016). This harmful allele i.e.
X-linked trait has passed to one of the offerings of four sons, who had died at the age of 30 only.
While two daughters among five were act as carriers who further transmit the same altered gene
into their offerings.

2.3 Explain the role of chromosomal abnormalities in inheritance of Down's syndrome
Chromosomal abnormalities can be defined as extra or missing pair of chromosomes as
well as an irregular portion of chromosomal DNA. Therefore, it is organised into two main basic
groups as numerical and structural anomalies (Li and et. al., 2015). Along with this, it is usually
occurred when there is an error within cell division either in meiosis or mitosis. This error in cell
division results to cause down's syndrome within a living body. Down syndrome refers to a
chromosomal condition which is associated with intellectual disabilities. Genetic materials are
stored in genes that carry the codes which are responsible for entire inherited traits. In this
regard, any additional genetic materials cause to alter the developmental course and
characteristics, that are associated with down syndrome. This results in low muscle tone, upward
slant to eyes, small stature and more, where each individual having genetic syndrome possess
such characteristics to various degrees (Vaidyanathan and et. al., 2016). In general, as per
chromosomal changes, down syndrome can be distinguished in various types as Trisomy 21
(Non-disjunction), Mosaicism, Translocation and more. Here, non-disjunction leads to develop
an embryo including three copies of chromosomes rather than two. While mosaic down
syndrome is diagnosed when there is one extra pair of chromosomes. Other than this, within
translocation, number of chromosomes are still remained 46 but a pair of chromosomes is
attached with another one and causes down syndrome.
3.1 Describe process of genetic screening
Genetic testing can be defined as a type of medical test which is used to identify the
changes in genes, level of proteins and chromosomes (Tamparo, 2016). Through genetic test,
medical professionals can determined the chance of genetic disorder of an individual. It includes
various methodologies as given below:-
 Molecular genetic tests which studies the single genes for identification of mutation or
variations in body, that further leads to genetic disorder.
 Biochemical genetic test that measures the activity level of proteins or abnormalities in
DNA which results in genetically disorder.

 The another genetic testing includes chromosomal test which analyse the number of
chromosomes to determine causes that may create disabilities.
Genetic test is performed on a sample of hair, skin, blood, tissue or fluid which surrounds
the fetus while pregnancy (Garn, 2017). This sample is further sent to laboratories where medical
professionals look out for specific chromosomal changes, DNA or level of protein depending as
per suspicious disorder of an individual as shown below:-
(Source: Living in brave new genomic era. 2018)
3.2 Describe the application of DNA recombinant technology in treatment of a named medical
condition
Recombinant DNA technology (rDNA) is one of the most invented tool that opens up a
new age within modern biotechnology. Here, a person suffering from genetically disorder is
treated by identifying a gene or multiple genes then altering the genetic material another
organism, for enhancing characteristics within human body (Lewis, 2016). In this process,
various human proteins are produced in human like growth hormones, insulin and more for
treatment, as described below:-
Illustration 1: Type of Genetic Testing

 Insulin: This hormone is secreted in the pancreases by islet cells and control the glucose
level in humans who are suffered from certain type of inherited diseases, called diabetes
(Hegarty and et. al., 2015).
 Vaccine: It is a biological substance that is prepared from suspension of dead pathogenic
cells and injected into human body, for enhancement of antibodies against specific
antigens. It helps in treatment of herpes, hepatitis, mouth and foot diseases etc.
 Human Growth Hormones: It refers to polypeptide hormone which is responsible for
regeneration of new cells like somatotroph present within pituitary gland, for developing
growth of a person.
 Antibiotics: These are the chemical substance that are used for treating bacterial
infections, which helps in destroying harmful bacteria and microbes causes infections.
3.3 Describe moral and ethical issues raised by DNA recombinant technology
Recombinant technology involves the process of combining DNA of one organism to
another therefore, involves various moral and ethical issues (Root-Bernstein and Root-Bernstein,
2016). It includes:-
 rDNA may produce harmless micro-organism which may become pathogenic that impact
negatively on living bodies.
 Combining animal and human DNA results in chimeric entities may create a long-term
effect on environment.
 Health risks are also associated with insertion of extra genes or genetically modified
chromosomes. There is a high potential of increasing issues related with transgenic
organisms.
 Crossing species is unethical and immoral activity that violated the natural laws.

REFRENCES
Books and journals
Catalanotto, C., Cogoni, C. and Zardo, G., 2016. MicroRNA in control of gene expression: an
overview of nuclear functions. International journal of molecular sciences. 17(10).
p.1712.
Devineau, S. and et. al., 2016. Protein adsorption and reorganization on nanoparticles probed by
the coffee-ring effect: application to single point mutation detection. Journal of the
American Chemical Society. 138(36). pp.11623-11632.
Gladyshev, E. and Kleckner, N., 2016. Recombination-independent recognition of DNA
homology for repeat-induced point mutation (RIP) is modulated by the underlying
nucleotide sequence. PLoS genetics. 12(5). p.e1006015.
Pollard, T. D. and et. al., 2016. Cell Biology E-Book. Elsevier Health Sciences.
Radhakrishnan, A. and Green, R., 2016. Connections underlying translation and mRNA
stability. Journal of molecular biology. 428(18). pp.3558-3564.
Root-Bernstein, R. and Root-Bernstein, M., 2016. The ribosome as a missing link in prebiotic
evolution II: ribosomes encode ribosomal proteins that bind to common regions of their
own mRNAs and rRNAs. Journal of theoretical biology. 397. pp.115-127.
Hegarty, R. and et. al., 2015. Inherited metabolic disorders presenting as acute liver failure in
newborns and young children: King’s College Hospital experience. European journal
of pediatrics, 174(10), pp.1387-1392.
Lewis, R., 2016. Human genetics: the basics. Garland Science.
Hernandez, D. G., Reed, X. and Singleton, A. B., 2016. Genetics in Parkinson disease:
Mendelian versus non‐Mendelian inheritance. Journal of neurochemistry, 139, pp.59-
74.
Li, S. and et. al., 2015. In silico identification of protein S-palmitoylation sites and their
involvement in human inherited disease. Journal of chemical information and
modeling, 55(9), pp.2015-2025.
Tamparo, C. D., 2016. Diseases of the human body. FA Davis.
Vaidyanathan, R.and et. al., 2016. I K1-enhanced human-induced pluripotent stem cell-derived
cardiomyocytes: an improved cardiomyocyte model to investigate inherited arrhythmia
syndromes. American Journal of Physiology-Heart and Circulatory
Physiology. 310(11). pp.H1611-H1621.
Garn, S. M., 2017. Human races. Pickle Partners Publishing.
Wojtal, D. and et. al., 2016. Spell checking nature: versatility of CRISPR/Cas9 for developing
treatments for inherited disorders. The American Journal of Human Genetics, 98(1),
pp.90-101.
Online
Sex Linked Genes. 2012. [Online] Available
Through:<https://www2.palomar.edu/anthro/biobasis/bio_4.htm>.
Living in brave new genomic era. 2018. [Online] Available
Through:<https://www.risingtidebio.com/review-dna-genetic-testing/>.