Migle Mikalajunaite 000800100 Biology Essay
University of Greenwich
Migle Mikalajunaite
Student ID: 000800100
Modes of the inheritance of genetic diseases in human
The body of a human is made up of cells. Even if all the cells have different functions, which leads to different structure of the cell, essentially all cells are similar: all have nucleus, surrounded by cytoplasm. Nucleus importance in inheritance is clear when it comes to its’ structure: in somatic cells, nucleus contains 23 pairs of chromosomes [ref.Genetics - Genetic inheritance 2012] where DNA, the genetic material, is present. One chromosome in the pair is inherited from the mother; one from the father. Different forms of the same gene are called alleles, they can be dominant or recessive, and they arise when DNA code mutates. These DNA code mutations can be neutral and show no effect in human; it may be beneficial; but also it can cause a disease. Different diseases are being inherited through different patterns. Huntington 's disease is inherited through Autosomal dominant pattern; cystic fibrosis – through autosomal recessive; Rett 's syndrome – through X-Linked Dominant; Haemophilia A – through X-Linked recessive [ref. Heidi Chial, Ph.D; 2008] It is important to know inheritance patterns to acknowledge how disease is transmitted, also to predict the risk of recurrence for relatives.
Figure 1: Autosomal dominant disorder
A disease or disorder can be inherited in an autosomal dominant pattern (Figure 1). One abnormal gene, which is located on one of the 22 non-sex determining chromosomes, from one of the parents, will lead to inheriting a disorder. [ref. Genetics Basics - Lesson 3] It happens because of dominant mutant allele condition. Each individual’s peril is independent and there is risk of 50% to inherit abnormal gene, as affected person is carrying one copy of normal gene and one copy of mutant gene. Individuals who do not inherit the mutant allele, will not have a chance of passing the disease. [ref. Feero WG, Zazove P,
Migle Mikalajunaite
Student ID: 000800100
Modes of the inheritance of genetic diseases in human
The body of a human is made up of cells. Even if all the cells have different functions, which leads to different structure of the cell, essentially all cells are similar: all have nucleus, surrounded by cytoplasm. Nucleus importance in inheritance is clear when it comes to its’ structure: in somatic cells, nucleus contains 23 pairs of chromosomes [ref.Genetics - Genetic inheritance 2012] where DNA, the genetic material, is present. One chromosome in the pair is inherited from the mother; one from the father. Different forms of the same gene are called alleles, they can be dominant or recessive, and they arise when DNA code mutates. These DNA code mutations can be neutral and show no effect in human; it may be beneficial; but also it can cause a disease. Different diseases are being inherited through different patterns. Huntington 's disease is inherited through Autosomal dominant pattern; cystic fibrosis – through autosomal recessive; Rett 's syndrome – through X-Linked Dominant; Haemophilia A – through X-Linked recessive [ref. Heidi Chial, Ph.D; 2008] It is important to know inheritance patterns to acknowledge how disease is transmitted, also to predict the risk of recurrence for relatives.
Figure 1: Autosomal dominant disorder
A disease or disorder can be inherited in an autosomal dominant pattern (Figure 1). One abnormal gene, which is located on one of the 22 non-sex determining chromosomes, from one of the parents, will lead to inheriting a disorder. [ref. Genetics Basics - Lesson 3] It happens because of dominant mutant allele condition. Each individual’s peril is independent and there is risk of 50% to inherit abnormal gene, as affected person is carrying one copy of normal gene and one copy of mutant gene. Individuals who do not inherit the mutant allele, will not have a chance of passing the disease. [ref. Feero WG, Zazove P,
Bibliography: Dr Ananya Mandal, MD. (2013). Chromosomal theory of Inheritance.Available: http://www.news-medical.net/health/Genetic-Inheritance.aspx. Last accessed 3rd April 2014. Feero WG, Zazove P, Stevens NG Genetic Basics Lesson 3. (2014). Modes of Inheritance. Available: http://hihg.med.miami.edu/code/http/modules/education/Design/Print.asp?CourseNum=1&LessonNum=3.Last accessed 3rd April 2014. Genetics - Genetic inheritance. (2012). How genetic conditions are inherited. Available: http://www.nhs.uk/Conditions/Genetics/Pages/Facts.aspx. Last accessed 2nd April 2014. Genetics Home Reference. (2012). Cystic fibrosis. Available: http://ghr.nlm.nih.gov/condition/cystic-fibrosis. Last accessed 3rd April 2014. Genetics Home Reference. (2012). Hemophilia A. Available: http://ghr.nlm.nih.gov/condition/hemophilia. Last accessed 3rd April 2014. Genetics Home Reference. (2014). Huntington disease. Available: http://ghr.nlm.nih.gov/condition/huntington-disease. Last accessed 2nd April 2014. Genetics Home Reference. (2013). Rett Syndrome. Available: http://ghr.nlm.nih.gov/condition/rett-syndrome. Last accessed 2nd April 2014.