What Changes In The Genome Have Produced Chondrodysplasia In Dogs Case Study
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Homework Assignment 3
1. Two hypotheses have been proposed for the phenotypic variability observed in dogs. First, dogs may have genomes that are prone to mutation, and second, domestication may have allowed negative mutations to persist in the population. While the paper does not disprove either of these hypotheses, it offers an alternative mechanism for the development of dwarf stature (chondrodysplasia) in certain dog breeds.
a. What changes in the genome have produced chondrodysplasia in dogs?
One of the most common source through which novel sequence is acquired in genome evolution is Retro transposition of processed mRNAs (Heidi p.996). Fibroblast growth factor 4 (fgf4), which was recently acquired through retro gene encoding, is one of the chief reasons behind the production of chondrodysplasia in dogs.
b. Development of what part of the …show more content…
This haplotype contained a 5kb insert in chondrodysplastic dogs only. Sequencing of this insert revealed it a FGF4 retro gene. What is a retro gene? How did the researchers know this was a retro gene, rather than a simple duplication of the FGF4 gene?
Retro genes are caused by reverse transcription of the mature messenger RNAs. Therefore, they contain no introns. Worth noting, the FGF4 gene is naturally duplicated through retro-transposition, which differs from reverse transcription in Retro genes.
d. Was the FGF4 retro gene expressed in chondrodysplastic dogs? How did they tell it apart from normal FGF4 expression?
Yes, the whole genome sequence suggests that the FGF4 gene expression was high in chondrodysplastic dogs that were characterized with short limbs. The distinction between the two types of gene expressions can be made on basis that FGF4 expression would lead to phenotypic variability in chondrodysplastic dogs.
3. Figure 4 shows restriction enzyme digestion of a PCR amplified 500bp fragment of the 5’ end of cDNA from FGF4 and/or the FGF4 retro
Professor’s Name
Subject
DD Month YYYY
Homework Assignment 3
1. Two hypotheses have been proposed for the phenotypic variability observed in dogs. First, dogs may have genomes that are prone to mutation, and second, domestication may have allowed negative mutations to persist in the population. While the paper does not disprove either of these hypotheses, it offers an alternative mechanism for the development of dwarf stature (chondrodysplasia) in certain dog breeds.
a. What changes in the genome have produced chondrodysplasia in dogs?
One of the most common source through which novel sequence is acquired in genome evolution is Retro transposition of processed mRNAs (Heidi p.996). Fibroblast growth factor 4 (fgf4), which was recently acquired through retro gene encoding, is one of the chief reasons behind the production of chondrodysplasia in dogs.
b. Development of what part of the …show more content…
This haplotype contained a 5kb insert in chondrodysplastic dogs only. Sequencing of this insert revealed it a FGF4 retro gene. What is a retro gene? How did the researchers know this was a retro gene, rather than a simple duplication of the FGF4 gene?
Retro genes are caused by reverse transcription of the mature messenger RNAs. Therefore, they contain no introns. Worth noting, the FGF4 gene is naturally duplicated through retro-transposition, which differs from reverse transcription in Retro genes.
d. Was the FGF4 retro gene expressed in chondrodysplastic dogs? How did they tell it apart from normal FGF4 expression?
Yes, the whole genome sequence suggests that the FGF4 gene expression was high in chondrodysplastic dogs that were characterized with short limbs. The distinction between the two types of gene expressions can be made on basis that FGF4 expression would lead to phenotypic variability in chondrodysplastic dogs.
3. Figure 4 shows restriction enzyme digestion of a PCR amplified 500bp fragment of the 5’ end of cDNA from FGF4 and/or the FGF4 retro