Help! i dont get genetics and heredity?

Question

I have this project i have to do and it needs to be about heredity but every website i go on to try and understand they are all too technical and make absolutely no sense, especially the parts about heterozygous and homozygous, Oh alleles comfuse me too. THANKS!

Answer 1

Agree with the poster above, Mendel's experiments would be an interesting project.

Genes are sections of our DNA that contain instructions for making proteins. Proteins are basically the molecules that make up your entire body and make you who you are. If you have different types of proteins from someone else, then you will have different traits from that person.

Your genes are stored in DNA, which is condensed into packages called chromosomes. These chromosomes are in every cell in your body, and they tell that cell what to do & what proteins to make. Humans have 23 different chromosomes, and each one carries many different genes. We also have 2 copies of each chromosome, so in total we have 46 chromosomes. One set of 23 is inherited from your mother, and the other 23 from your father.

The word allele comes into play because of these copies. For example, the gene for the trait of eye color is on chromosome 19. Because you have two chromosome #19s, you have two genes for eye color. Those two genes can either be the same or different. If they are the same (ie they both say brown eyes), then you are homozygous for eye color (homo means 'same'). If they are different (ie you have one gene for blue and a gene for brown on the other chromosome), then you are heterozygous for that trait (hetero means 'different').

The word allele just means that there are different versions of the eye color gene, such as the brown allele or the blue allele.

Answer 2

Simple answers:
Most people are confused by alleles because they use the term gene when they should use the term allele. Let's say you have some plants that are the same species. Some of the plants are tall, some are short. All the plants have the same gene regulating height but they differ in the height allele. Those that are short have the short allele; those that are tall have the tall allele. In sexually reproducing organisms half the DNA comes from one parent half from the other, so everyone has two copies of each allele. Usually one of the alleles is "dominant" and one is "recessive". So let's say that in the plants the tall allele is dominant and the short is recessive. Homozygous plants would have both alleles that are the same, either both tall or both short. Heterozygous plants would have one short allele and one tall. Since the short allele is the recessive one only plants that are homozygous for the short allele will become short. All the heterozygous plants will be tall since the tall allele is dominant.
Hope that is simple enough.

Answer 3

1. Alleles are just the different forms of a gene for a trait. It's just like how ice cream has different flavors. A gene has different "flavors". The gene for seed shape may have two alleles or flavors ... round or wrinkled. The gene for human blood type has three possible alleles or flavors ... A, B, and O.

2. Homozygous means that the individual has two alleles that match. Maybe they both say round seed shape, so the genotype is RR. Or the person has two alleles for blood type and they both say A (AA) or both say B (BB). I tell my students that homo- means "same", so homozygous is same-o-zygous. rr, not Rr.

3. Heterozygous means that the individual has two alleles that are different; they don't match. Maybe one allele says round seeds and the other allele says wrinkled seeds - Rr. Or the person has one blood type allele that says A and another that says O ... AO. Hetero- means "different" or "other". Think of the Ts in these words: heTero, differenT, oTher.

Answer 4

Definitions that will be helpful:
1. Gene: a collection of bases (A, T, C and G) in the chromosome that code for a specific protein or trait; an example would be the gene for eye color
2. Locus: the place on the chromosome where a gene is located
3. Allele: the different variations of a gene. Alleles for eye color might be brown, blue, etc.

As for hetero/homo-zygous, you should know that humans have two sets of chromosomes: one from the mom, and one from the dad. When you have two sets, labeled 2n (where n is the chromosome number in one set), this is called diploidy. Haploidy is when you have only one set (n).
This means that humans have two alleles for every gene - one from mom, one from dad.

4. Heterozygous: having two different alleles for the same gene. For example, in the eye color example, you'd have an allele for brown eyes and one for blue eyes.
5. Homozygous: having the same alleles at one gene. So, you'd have two blue eye alleles, one on each chromosome.

I hope that helps! Post more questions as needed, or e-mail me. Good luck!

Answer 5

The Mendel idea is perfect. It illustrates very well the basic concept of heredity and how it is tied to genes. But if you have questions or want additional ideas, I'm a geneticist trained at Harvard and Stanford with twenty years of experience as a practicing geneticist and would be happy to help. [e-mail]. This is free, of course. I would not give out this email otherwise.

Answer 6

Try reading about Gregor Mendel and his work with peas. It explains the subject in a very simple form, and it's a project that would be easy to replicate.

Good luck.

Answer 7

Apparently a lot of people have a genetic condition that drives them to buy house, but then makes them default on their mortgages.....and other people who are genetically pre-disposed towards paying higher taxes have to pick up the tab.

Answer 8

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