I dont understand genetics, what are Alleles and what are dominant and resecive genes?

Question

In homeschooling my teacher started me and my class mates on genetics i don't know how do do it.

Answer 1

Alleles are the two different chromosomes you have for each pair of chromosomes.
Recessive genes need to exist in both alleles in order to be expressed.
Dominant genes are expressed by existing at least in the one allele.
If x is dominant and y is recessive, the combination xx expresses x, the combination xy also expresses x and only the combination yy expresses y.

Answer 2

Alleles are always hard for kids to understand - I think it's because the word allele is kind of strange.

Alleles are just different forms of a gene for a trait. So if the gene is for "handed-ness", then a person might get one gene that says right-handed from his mother and one gene that says left-handed from his father. Those different forms of the gene are alleles. I tell my students that alleles are kind of like flavors. If ice cream only came in chocolate and vanilla, then ice cream would have two alleles. But ice cream comes in a lot of different flavors or forms, so it has many alleles.

People who have a widow's peak (that little point of hair in the middle front that sticks down toward their forehead) must have an allele for widow's peak. Widow's peak is dominant, so anybody only has to get one of those alleles to have the widow's peak. The other allele can be widow's peak or straight hairline. Straight hairline is recessive. So a person with a straight hairline have two matching alleles for straight hairline - two of the recessive alleles. The dominant allele doesn't let the recessive allele show at all. It can be there, but it has to "keep quiet". The recessive allele only gets to show when there are two recessives and no dominant.

Answer 3

Alleles are different forms of the same gene for example, Y and y are different alleles of the gene that determines seed color. Dominant genes are genes which characteristics are always expressed, and recessive genes are genes which characteristics are only shown when not paired with a dominant. Rescessive are kinda funny, because their traits are not always expressed. For example, genes for brown hair are dominant and blonde hair genes are recessive. This is why my brown haired parents can produce a child with blonde hair. They can both carry the recessive gene in them, but they have brown hair because it is dominant and therefore expressed.