Talk:Mendelian inheritance
From Academic Kids
Could somebody with a better knowledge of genetics correct this sentence?
- Mendel based his theory on they could be both cross-pollinated between two plants or self-pollenated with just one.
silsor 04:49, Jan 23, 2004 (UTC)
Moved this from the article, I think most of this is already covered in the article and other didn't realize that this kind of information belongs in Talk, but I haven't checked closely. --Lexor|Talk 10:25, 23 Feb 2004 (UTC)
The parts of the previous version I didn't merge. Someone please have another look.
Mendel's First Law: Each adult pea plant has two genes - a gene pair - for each characteristic. The two members of each gene pair separate (segregate) randomly into the eggs or sperm of the plant, so that each egg or sperm contains only one member of each gene pair. The offspring therefore inherits one randomly selected gene from each parent for each characteristic.
The first law of Mendelian Genetics was easily illustrated due to the phenomenon of dominance. Certain characteristics, such as yellow seeds, were found to be "dominant" over other "recessive" characteristics, in this case over green seeds. A yellow-seeded plant crossed with a green-seeded plant produced offspring that were entirely yellow-seeded. However, when these yellow-seeded offspring were crossed with the original green-seeded parent strain (a procedure known as back-crossing), half of the plants in the second offspring generation bore yellow seeds and half bore green seeds. The following diagram illustrates these crossesdominant yellow characteristic and a lower-case y to indicate the recessive green characteristic. These two variants are called alleles of the gene.
YY X yy Parental generation (P)
| V Yy First generation of offspring (F1) All seeds are yellow (Y allele is dominant)
Yy X yy Second cross, F1 with green P | V Yy and yy Second generation of offspring (F2), with an equal proportion of Yy and yy
Mendel's Second Law: During the formation of sperm and egg, the segregation of alleles for one gene is independent of the segregation of alleles for another gene. This law was slightly more complex to demonstrate, requiring the statistical analysis of offspring of plants that differed in two separate characteristics. typing hands getting tired, put this demo in later
Order of article?
When I came across this article, I found it rather counter-intuitive, in that Mendel's second law comes before the law of segregation, which I believe is his first. Is there a reason I'm missing for this order? The one I can think of is that the law of independent assortment (the second law) is linked to metaphase I, which comes before anaphase I in meiosis. But in my AP Biology textbook, Biology, the law of segregation precedes the law of independent assortment. Auricfuzz 01:19, Jan 19, 2005 (UTC)
- I too was confused by that, and I support the reordering of these parts of the article so that Mendel's First Law comes before his Second Law. — Brim 02:36, Jan 19, 2005 (UTC)
Scrambled text
If the two alleles differ, then one, the dominant allele, is fully expressed in the organism's appearance; the other, the segregate during gamete production.
The above sentence doesn't make sense. I looked through the article's history and found this old version (http://en.wikipedia.org/w/index.php?title=Mendelian_inheritance&oldid=369766) which shows that the sentence was created by splicing two pre-existing sentences and leaving out the bit in the middle. Sorry I can't fix it myself, but I don't understand the subject well enough (that's why I'm reading the article) and would probably make it worse. --Heron 19:24, 28 May 2005 (UTC)
