I saw an article about an extinct species of ibex that was cloned from frozen tissue. Unfortunately, the cloned animal died soon after birth due to lung defects. The article said that other cloned animals also suffer from similar lung defects. What exactly are the defects? And why are cloned animals more likely to have these defects? Thanks!

It's because there is more to the genetic code than just the basepairs of DNA. There are additional 'epigenetic' factors that we don't yet fully understand or know how to influence. An exampe of one of these factors is methylation, a modification on the spine of DNA which effects how proteins interact with the different regions of DNA.

The epigentics factors are like addition instructions on how and when to read the code. These are required to produce the correct result- the healthy animal.

I'm afraid I don't know what the exact defects are as I don't know which articlestudy you have read.

My guess is that if the scientist who were working on the clone knew why the lungs were defective they would have tried to do something about correcting it.