DNA
pedigrees
In today’s society, family trees have been constructed as to show the passing of families over generations past. Scientifically, family trees are used as to determine particular traits and characteristics inherited by every generation over time. Family trees can also be termed in this instance, pedigrees.
In order to actually understand pedigrees, further to articulate them, they are in need to be constructed. They can be range to be very small to excessively large depending on the breeding and individual perspectives. There are many labels and signs as to identify specific individuals within a family, furthering how they so-call link up to one another.
In order to actually understand pedigrees, further to articulate them, they are in need to be constructed. They can be range to be very small to excessively large depending on the breeding and individual perspectives. There are many labels and signs as to identify specific individuals within a family, furthering how they so-call link up to one another.
- Males are represented by a square.
- Females are represented by a circle.
- Both male and female whom are affected by the characteristic studied, have their specified shapes shaded in.
- Those whom are married have a horizontal line connecting each other as they are now neighbouring individuals.
- Not as common but when relatives or those whom are close in relation marry one another, a double horizontal line is drawn connecting the two.
- Individuals who are deceased have a diagonal line as though the diameter of the shape.
- As for children, it begins from the horizontal line connecting the married parents. A vertical line is drawn central down from the horizontal line. Once the next filial generation line-up is reached, children (he/she) are drawn in.
Once a pedigree is drawn, it must be further labelled. It is to the left hand side of the pedigree that roman numerals are aligned vertically counting down; showing the number of generations presented. Each individual its given generation is given a normal number counting left to right. This system allows s CONSTRCUTING PEDIGREES
There are many human characteristics which can be expressed in pedigrees, examples include: Skin colour, hair colour, eye colour, tongue rolling per say and much more. Today we are going to focus on Tongue rolling and explaining how to interpret this pedigree, further investigating rules as to understand pedigrees.
This is an image of a pedigree displaying tongue rolling within a family over 3 generations. As we know, males are represented by squares, females by circles and those whom are shaded are known to be affected; in this instance, affected refers to individuals who can roll their tongues. To articulate this trait, it is required that the genotypes/alleles for each individual are noted of. Scientists to specifically point out individuals, aiding others as to locate where within the pedigree they are and know focusing on.
There are many human characteristics which can be expressed in pedigrees, examples include: Skin colour, hair colour, eye colour, tongue rolling per say and much more. Today we are going to focus on Tongue rolling and explaining how to interpret this pedigree, further investigating rules as to understand pedigrees.
This is an image of a pedigree displaying tongue rolling within a family over 3 generations. As we know, males are represented by squares, females by circles and those whom are shaded are known to be affected; in this instance, affected refers to individuals who can roll their tongues. To articulate this trait, it is required that the genotypes/alleles for each individual are noted of. Scientists to specifically point out individuals, aiding others as to locate where within the pedigree they are and know focusing on.
Tongue rolling is a recessive characteristic, but without knowing that, how could you tell this was a recessive trait? As the characteristic has skipped a generation, it must be recessive. As for the genotypes, individuals who are shaded must all have an allele of aa. This means all individuals who are not shaded must be either homozygous AA or heterozygous Aa, thus a carrier.
Individual i2 in the parental generation is either AA or Aa. Looking at the offspring produced, not one child has the recessive trait of tongue rolling, thus all the children must possess at least the allele A. In order for this to be, i2 must have the genotype of AA, to ensure that all the offspring have trait present. What is resulted from crossing homozygous AA with aa is offspring all having the genotype of Aa.
III1, is the affected offspring of (not-affected) parents in the first filial generation; thus having the genotype aa. For this recessive genotype to be, the opposing parent of the non-affected parent must either be Aa or aa. Since II1 is not shaded in, they must have the genotype Aa, in order to have a recessive affected child. This concept goes for II5, as they bare one child with the recessive trait yet their spouse is not affected, nor are they, finalizing this indidvual to have the genotype Aa. For offspring III2, III3 and III5, they are all in the same boat. Both sets of parents had the 25% chance of baring a child with tongue rolling traits, which they did. This means there was a 50% chance they received the genotype Aa and a 25% chance of receiving the genotype AA. These 3 individuals as a part of the second filial generation can contain the genetic information of either AA or Aa.
The following is a link to a PDF document/PowerPoint, guiding you as simply as possible as to learn determining pedigrees. It lays out the foundation of pedigrees and explains the rules of follow when understanding genotypes and how they are affected. {CLICK THIS LINK}
PROBABILITY
Mathematically, scientists determine the probability of offspring inheriting a characteristic through simple algebraic expressions. These can be expressed in the form of fractions (½ , ¼), decimals (0.25, 0.5, 0.66), and percentages (20%, 50%, 75%).
PREDICTIONS
Pedigrees purpose themselves as to articulate the abundance of related affected family members, thus making a prediction through possibility calculations. Thus needed to investigate patterns related to a particular genetic disorder within a family. Single-gene disorders are caused by a single defected gene inherited over time. There has been over 4000 diagnosis’ for this affect with most being dominant trait related.
DOMINANT INHERTIANCE
This inheritance refers to the dominant allele being what expresses the characteristic at hand. An example of this is Huntington’s disease. This disease is incurable but what is worse is that its unidentified until 40 years of age. This disease refers to the incapability of controlling the limbs of the body. There is major difficulty in undergoing voluntary movements and there’s notable shaking of the head, arms and legs. This is controlled by a dominant allele. Other dominant traits carrying disorders include: Achondroplasia, Neurofibromatosis and Faciocapulohumeral.
RECESSIVE INHERITANCE
Unlike dominant inheritance, both alleles of an individual must be recessive. Those whom possess one allele dominant and one allele recessive are deemed carriers. Some diseases in relation to recessive inheritance traits are thalassemia, phenylketonuria and cystic fibrosis.
GENETIC COUNCILLING
Parents may be concerned as to whether they bear children or not. It is in this instance that the worry leans towards parents not wanting their potential children to inherit diseases to which they’ve suffered or are carriers of. Couples in recent times are leaning towards seeking advice on these issues at hand. Advice given in these situations is known as genetic counselling. This is where pedigrees are introduced and are examined as to the chances of a couples’ children having the disorder or not. Ultimately it is up to the parents as to risk having children or not, the councillors are there to give advice and awareness on the parents’ concern.
THE HUMAN GENOME PROJECT
Began 1990, refers to the mapping out of chromosomes of humans. Scientists began by mapping and interpreting all 46 separate chromosomes of the human body. The project was completed in 2003. To learn more about the human genome project, {click on the following link}
The following is a link to a PDF document/PowerPoint, guiding you as simply as possible as to learn determining pedigrees. It lays out the foundation of pedigrees and explains the rules of follow when understanding genotypes and how they are affected. {CLICK THIS LINK}
PROBABILITY
Mathematically, scientists determine the probability of offspring inheriting a characteristic through simple algebraic expressions. These can be expressed in the form of fractions (½ , ¼), decimals (0.25, 0.5, 0.66), and percentages (20%, 50%, 75%).
PREDICTIONS
Pedigrees purpose themselves as to articulate the abundance of related affected family members, thus making a prediction through possibility calculations. Thus needed to investigate patterns related to a particular genetic disorder within a family. Single-gene disorders are caused by a single defected gene inherited over time. There has been over 4000 diagnosis’ for this affect with most being dominant trait related.
DOMINANT INHERTIANCE
This inheritance refers to the dominant allele being what expresses the characteristic at hand. An example of this is Huntington’s disease. This disease is incurable but what is worse is that its unidentified until 40 years of age. This disease refers to the incapability of controlling the limbs of the body. There is major difficulty in undergoing voluntary movements and there’s notable shaking of the head, arms and legs. This is controlled by a dominant allele. Other dominant traits carrying disorders include: Achondroplasia, Neurofibromatosis and Faciocapulohumeral.
RECESSIVE INHERITANCE
Unlike dominant inheritance, both alleles of an individual must be recessive. Those whom possess one allele dominant and one allele recessive are deemed carriers. Some diseases in relation to recessive inheritance traits are thalassemia, phenylketonuria and cystic fibrosis.
GENETIC COUNCILLING
Parents may be concerned as to whether they bear children or not. It is in this instance that the worry leans towards parents not wanting their potential children to inherit diseases to which they’ve suffered or are carriers of. Couples in recent times are leaning towards seeking advice on these issues at hand. Advice given in these situations is known as genetic counselling. This is where pedigrees are introduced and are examined as to the chances of a couples’ children having the disorder or not. Ultimately it is up to the parents as to risk having children or not, the councillors are there to give advice and awareness on the parents’ concern.
THE HUMAN GENOME PROJECT
Began 1990, refers to the mapping out of chromosomes of humans. Scientists began by mapping and interpreting all 46 separate chromosomes of the human body. The project was completed in 2003. To learn more about the human genome project, {click on the following link}
Pedigree bibliography
All the following references where collected on the 12/10/14
All the following references where collected on the 12/10/14
- www.homepages.uel.ac.uk-, from google images, retrieved 12:09pm
- www.adapaproject.org-, from googles images, retrieved 12:10pm
- www.bibliotecapleyades.net-, from google images. Retrieved 12:15pm
- http://www.biology-online.org/dictionary/Pedigree, title: pedigrees, what are they? Retrieved 1:00pm
- http://www.bogari.net/Bogari/Medical_Genetics_files/3-1%20Patterens%20of%20Inheritance.pdf, title: autosomal recessive PDF, retrieved 1:07pm
- http://www.hdsa.org/, title: Huntington’s disease, retrieved 1:09pm
- http://ghr.nlm.nih.gov/condition/achondroplasia, title: genetics home reference retrieved 1:27pm
- http://ghr.nlm.nih.gov/condition/facioscapulohumeral-muscular-dystrophy, title: muscular dystrophy, retrieved 1:30pm
- http://en.wikipedia.org/wiki/Cystic_fibrosis, title: cystic fibrosis, retrieved 1:31pm
- http://www.nlm.nih.gov/medlineplus/ency/article/000587.htm, title: thalassemia, retrieved 1:37pm
- http://www.genome.gov/10001772, title: human genome project, retrieved 2:02pm
- http://www.zerobio.com/drag_gr11/pedigree/pedigree_overview.htm, DROP AND DRAG PEDIGREE GAME, retrieved 2:09pm
- The constant use of Human Perspective 2A/B written by TJ Newton and AP Joyce