Gene linkage is the ability of DNA sequences that are close together usually on a chromosome to be inherited together.
during the meiosis in sexual reproduction two genes that are physically close to each other are not likely to separate from each other to different chromatids during chromosome crossover but are rather linked and inherited together. Genes that are close on the chromosome are said to be more linked than gene that are far apart.
If two genes on a chromosome are close there is low chance of recombination between them, and they are likely to be inherited together. Gene on different chromosomes are not linked.
When genes are on separate chromosomes, they tend to assort independently meaning that due to the random position/placement of the homologous chromosomes pair on the metaphor plate during meiosis, the homologous chromosomes assort independently.
If you're overfishing at the top of the food chain, and acidifying the ocean at the bottom, you're creating a squeeze that could conceivably collapse the whole system that's my answer
