Honors Biology Baby Project
15 April 2015
After having married my beloved wife named Kayla, we decided to have a child together. I am the proud father and Kayla is the proud mother of our new baby boy named Aidan Christopher. Kayla and I’s genetic counselor is named Akeem.
After having seen Aidan’s karyotype, it is sadly concluded that he has been diagnosed with Down syndrome. It appears on the karyotype as having three 21st chromosomes instead of the normal two. Some of the symptoms of this neither dominant nor recessive chromosomal disorder are the following: “flattened facial features, small head, short neck, protruding tongue, upward slanting eyes, unusual for the child's ethnic group, unusually shaped or small ears, poor muscle tone, broad, short hands with a single crease in the palm, relatively short fingers and small hands and feet, excessive flexibility, tiny white spots on the colored part (iris) of the eye called brushfield spots, and short height,” (Mayo Foundation for Medical Education and Research April 19, 2014).
The prognosis for babies born with Down syndrome have changed over the years because in the 1910s, the life expectancy was only nine years, but now it is common for 80% of the people with Down syndrome to live over fifty years. Children are still allowed to attend school, but they may need to be taught in a special needs class depending on the subject and their abilities. Children with Down syndrome still love different things like music, reading, and playing sports, etc., just like any other child. Adults however, may live with their families or in community homes, have jobs liking working in restaurants or offices, and they can marry and have children. Females however, are at a great risk of having a miscarriage. (Stanley J. Swierzewski ‘Published’ August 28, 2008 ‘Last modified’ December 2, 2014).
The treatments/assistance that is recommended for children with Down syndrome is the following: “early intervention and educational therapy, treatment therapies, drugs and supplements, and assistive devices.” For example, a child may have to have surgery to correct a heart defect or be on a life-long special diet to fix any digestive problems. “Children, teens, and adults with Down syndrome also need the same regular medical care as those without the condition, from well-baby visits and routine vaccinations as infants to reproductive counseling and cardiovascular care later in life. Like other people, they also benefit from regular physical activity and social activities,” (NIH ‘Last updated’ March 26, 2015).
The autosomal recessive allelic disorder that is indicated by my family history is Tay-Sachs disease. The predicted probability of our child getting this disorder, if my wife and I are both homozygous dominant, is 0%. If one of us is homozygous dominant and the other, heterozygous, the probability would still be 0%. If both of us are heterozygous, there will be a 25% chance that Aidan will have Tay-Sachs disease. “Tay-Sachs disease results when an enzyme that helps break down fatty substances is absent. These fatty substances build up to toxic levels in the child's brain and affect the nerve cells. As the disease progresses, the child's body loses function, leading to blindness, deafness, paralysis and death.” This disease must be inherited from the genes of both the parents in order to occur. “There is no cure for Tay-Sachs disease. Gene therapy or enzyme replacement therapy research may eventually lead to a cure or treatment to slow the progression of Tay-Sachs disease.” (Mayo Foundation for Medical Education and Research October 21, 2014).
The predicted blood type of our child is either A or B blood type. After working out a Punnett square, it is clear that when a person with AB blood type has children with someone that has O blood type, the child will have a 50% chance of having heterozygous A blood type or heterozygous B blood type. The reasons for these choices in blood type are due to the fact that I have O blood type and my wife, Kayla, has AB blood type.
Aidan Christopher has many traits and four of which, inherited by basic autosomal dominance or recessiveness, are the following: freckles, eye brows, lip thickness, and eyelashes. The genotype of his freckles is FF, it is homozygous dominant, and his phenotype is present. The genotype of his eye brows is Bb, it is heterozygous, and his phenotype is bushy. The genotype of his lip thickness is tt, it is homozygous recessive, and his phenotype is thin. The genotype for his eyelashes is LL, it is homozygous dominant, and his phenotype is long.
One trait that is inherited by incomplete dominance is his eye size. This is considered incomplete dominance because its definition is an intermediate of two traits and since his eye size is neither large nor small, it is medium and medium is an intermediate of large and small. Therefore, Aidan’s medium-sized eyes are inherited by incomplete dominance. The genotype of his eye size is S1S₂ and his phenotype is medium.
Polygenic traits are the traits which are coded for by more than one allele. One of the polygenic traits that Aidan has is his red hair and polygenic inheritance worked to give him that by giving him two alleles from me (his father) and two alleles from Kayla (his mother). I gave Aidan the alleles of A and A and Kayla gave him the alleles of b and b. Therefore Aidan Christopher’s genotype of his red hair is AA/bb and his phenotype is red.
"Down Syndrome." Symptoms. Mayo Foundation for Medical Education and Research, 19 Apr. 2014. Web. 07 Apr. 2015.
"Tay-Sachs Disease." Mayo Clinic. Mayo Foundation for Medical Education and Research, 21 Oct. 2014. Web. 07 Apr. 2015.