Question

Creighton and McClintock worked with ___ as their model system to show that homologous chromosomes physically exchange genetic information during crossing over?

1) fruit flies
2) bacteria
3) yeast
4) mice

Answer 1

Creighton and McClintock used corn plants to demonstrate the physical exchange of genetic information between homologous chromosomes during crossing over, solidifying our understanding of genetics and gene mapping.

Step-by-step explanation:

Creighton and McClintock worked with corn plants as their model system to show that homologous chromosomes physically exchange genetic information during crossing over.

In 1931, Barbara McClintock and Harriet Creighton performed groundbreaking experiments where they provided concrete evidence for the physical exchange of genetic material between homologous chromosomes - a process known as crossing over. They did this by analyzing corn plants' chromosomes and noting changes in color traits in the kernels that correlated with chromosome recombination events. Their work was pivotal for the field of genetics, solidifying the understanding that chromosomes carry hereditary information and exchange it during meiosis, which increases genetic diversity in offspring. This biological mechanism underlies the principles of Mendelian inheritance and has important implications for the mapping of genes on chromosomes.