**Title: Understanding Familial Down Syndrome**Familial Down syndrome is similar to primary Down syndrome as both are caused by trisomy 21. However, in familial Down syndrome, all or part of the third copy of chromosome 21 has translocated onto another autosome, typically chromosome 14. In such cases, one parent of the affected child is often a carrier of a translocated chromosome. The translocation carrier parent does not exhibit Down syndrome because they have two copies of chromosome 21.### Activity: Understanding Chromosome Translocations**Scenario:**A woman is a translocation carrier of chromosome 21 on chromosome 14. She conceives six zygotes with a normal man who carries no aneuploidies. Match the description of the chromosomes inherited by each zygote with the viability of the zygote.**Categories:**1. **Viable normal, or translocation carrier**2. **Viable, with Down syndrome**3. **Inviable****Answer Bank:**- Two normal copies of 21, one normal copy of 14- Two normal copies of 21, two normal copies of 14- One 21 to 14 translocation, one normal copy of 21, one normal copy of 14- One 21 to 14 translocation, two normal copies of 21, one normal copy of 14Assign each genetic combination to the appropriate category to understand how these combinations affect the viability and phenotype of the offspring. This exercise illustrates the genetic complexities involved in familial Down syndrome. The image contains a table with three categories and an answer bank. The task is to match the descriptions of chromosomes inherited by each zygote with its viability.### Categories:1. **Viable normal, or translocation carrier**2. **Viable, with Down syndrome**3. **Inviable**### Answer Bank:- Two normal copies of 21, one normal copy of 14- Two normal copies of 21, two normal copies of 14- One 21 to 14 translocation, one normal copy of 21, two normal copies of 14- One 21 to 14 translocation, two normal copies of 21, one normal copy of 14- One normal copy of 14, one normal copy of 21, one 21 to 14 translocation - Two normal copies of 14, one normal copy of 21This exercise helps understand chromosomal compositions associated with different viabilities, usually in the context of chromosomal abnormalities such as Down syndrome, involving trisomy or translocation events.

Name: **Title: Understanding Familial Down Syndrome**Familial Down syndrome
Uploaded: 2024-03-20T06:42:55.000Z
Channel: Bartleby
Description: **Title: Understanding Familial Down Syndrome**Familial Down syndrome is similar to primary Down syndrome as both are caused by trisomy 21. However, in familial Down syndrome, all or part of the third copy of chromosome 21 has translocated onto anot

Downs syndrome is the most common chromosomal disorder characterised by various clinical symptoms like stunted height,palmar crease, mongolian face, retardism etc.It is mainly caused due to the trisomy of 21st chromosome most likely due to non-dysjunction of chromatids during meiosis. However,although rare there is another type of downs syndrome with actually a two 21 chromosomes but an abnormal 21 chromosome attached to 14th chromosome (mainly) due to an abnormal translocation in either parent.A.Viable normal,Translocation carrier: . one 21 to 14 translocation,one normal copy of 21 with two normal copies of 14th chromosome. (Here , we see that the zygote has a normal number that is two 21st chromosome,and two 14th chromosome.Thus the zygote is genetically normal and hence be viable further but for the fact that it has a translocation present between 21 and 14 and thus will be a translocation carrier and may produce a familial downs syndrome in the next generation). .two normal copies of 21,two normal copies of 14. B.Viable ,with Downs Syndrome: .one 21 to 14 translocation,two normal copies of 21st chromosomes,one normal copy of 14. (Here we can easily see that three chromosomes (of 21st autosome) are present thus clinically presenting the patient to be of down's syndrome). C.Inviable: .two normal copies of 21,one 21 to 14 translocation,one normal copy of 14. .two normal copies of 21,one normal copy of 14. .one normal copy of 21,two normal copies of 14. (Here we see that the zygote is lacking a chromosome be it 21or 14 and hence being inviable.)