A few ideas for winning : )

❏      Remember to make a copy of this document. Then change the part that has my name to the college you are in and the semester and year to your name and first initial. 

❏      You will  turn in this whole document online, not just the answers. I also need the questions : )

❏       There is no quiz for this section

❏      Read the lecture note carefully in order to answer the questions. Avoid skimming because it makes it more difficult to answer the questions.

❏      If troubled there is a video.

❏      Answer the questions and turn-in.

Help video: Video Paul Andersen. Diploid vs. Haploid Cells. Bozeman Science

Now, if we shift from the idea that any trait is inherited by a species in a family lineage, AKA Mendel’s first law, the principle law of segregation, we can begin to see some of the other complexity in the basic inheritance model.

In this section we will review the idea of genes as opposed to taits. Think of traits as the whole cake and the genes as the precise instructions for how to use, make, and acquire the ingredients for the cake. The cake has traits for certain; the frosting, the decorations, the filling, the bread or cake layers, and the decorations. However, how to get what is needed and how to use it are not easily observed as are the traits.

The key concept we are using here is Mendel’s second law of independent assortment. Meaning, we are making the assumption based on previous work that traits are inherited from the parents. Next, we are trying to show how the instructions for a trait exist in independent packs.

The independent gene usually works in combination with other genes. To add to complexity genes can be expressed or not. Meaning , a gene may be present but not show, this is referred to as dominance and recessive.

As we have learned that cells contain DNA which activates things by using RNA, both are ractive and function to produce and build proteins which do things. The details for production are in the genes. How the genes show are the traits.

Simply stated cells contain DNA which uses RNA to build proteins and the information on how to do that are stored in genes as segments of the DNA. The things built are known as traits.

Gametes

Now, as we continue the exploration of inheritance we have established that cells are micro-machines which store all the things needed for production and function. In this lesson we are demonstrating Mendel's second law of independent assortment. Hence, we use the cell. There is a special kind of cell, a sex cell, referred to as a gamete, which is either a sperm or an ovum.

A sex cell gets one of the of alleles from each parent. An allele is a gene for something but is a variant form. For example,  is a gene for sex type is variant because it has a combination of X for male and Y for female. The offspring inherit the genes either xxs and or y from the parents. Consequently the genetic structure for offspring can vary. The X and Y are alleles.

 It is at times complex to understand genetics but for this course we will explore a few of the ideas. For example, an allele can be viewed with the ABo blood groups. That is, for humans we have three basic and understated alleles for blood; A , B, and o.

We have genetic types for blood which are similar but... what is not similar is the specific cell type. They are similar for blood, but not because of what type. They are similar because of the function but not type. Those parts of the gene which code for the type are alleles. There is an added complexity sometimes and rarely, one allele is truly dominant over another. In the expression of genes for humans in the ABo blood groups A and B are codominant. Meaning they coexist on more or less equal standing.

However, o type is not dominant and is referred to as recessive.  That is, type o is passive to A or B and will not change the blood to type o. This is not too complex so far. However, the truth be told it is far more complex such as when considering the ideas of Rh factors, what parts of a cell or gene are dominant and which are recessive become a more complex puzzle to build.

That is, basic Mendelian models for inheritance may not be adequate for resolving more complex issues but it is a start. There are reasons that more complex models need to be considered two are pleiotropy and polygenetics. Meaning that with pleiotropy, one gene can be used as a tool for many effects. Another iswith, polygenetics which uses more than one gene or for any one of many effects. It is not simple to start at the more complex and more accurate models.Therefore, it is useful to start with a two part model (refer to img.Gamete Selection 1 and 2) then to move onto more complex ones (refer to img.Gamete Selection 3) for example a much more complex 3 sets in two part model (refer to img.Gamete Selection 4). However, it is important to note the simple steps are not able to present the complexity of the human genome.    

Starting with some simple ideas, the genotypes for blood are different from the blood groups. For humans simply and usually blood groups are referred to as A, B,  and o. However, the groups are actually made of two alleles for the blood cell.  The alleles for A, B, or o types can combine in a two part system. A mother or a father must have at least two alleles but may have the alleles in combination. For example in an ABo blood group, a parent with type A has either genotype from below as a genotype. Both are simply named type A blood group.

1.AA (homozygous dominant) same

2.Ao (heterozygous) different

3.AB (codominant) both show

Blood also has other genotypes for example; if one parent has genotype AA blood and the other parent has genotype BB blood then the offspring will get one A from parent one and one B from parent two resulting in type AB blood (codominant) (refer to table1). This shows Mendel’s first law, the principle law of segregation.

However, a parent could be A for the blood group but their genotype could be Ao. This complicates the issue because now there are two sex cell options for blood grenotypes from that parent who has Ao alleles for A blood group, not just A but also an allelle for o.

Consequently, when we combine parent one with Ao with parent two BB the outcome is less clear because each parent passes on half of their genotype. In the case of parent two it is simply a B because there are no other choices. However, for parent one it is either A or o. Therefore the offspring of the two parents could inherit A, B or o because they are options. Meaning the offspring could be AB (codominant) or Bo (heterozygous). This shows Mendel’s second law of independent assortment that the traits exist in packets which can be transferred to offspring independently.

This can be shown in a handy tool known as a Punnett Square (refer to table 1 and table 2). It is used by placing one of the parent’s(p1)genotype in the first column and other parent’s (p2) on the top row.  Then using the intersections to predict the genotypic outcome of the offspring.

We know that trait alleles have at least two parts for simplified Mendalian genetics. That allows some easy applications. We do not have to use A, B, or o to represent any trait. We can use Aa, Bb, Cc, etc. because uppercase represents dominant and lower case represents recessive. Some prefer to use a letter as an allele which represents the idea for example, T for tall, t for small, etc…

All these ideas form together to show the principle law of segregation from Gregor Mendel, that all traits an offspring has comes directly from their parents. Also we show the principle law of independence that; traits can exist as separate from other traits and be passed down to offspring.

That being said, offspring get the genetic information from their parents and the parents pass part of the DNA to offspring separate from the whole DNA. A parent passed on part of the DNA through creating sex cells which have half the DNA required for a life. The sex cell is a gamete and comes as either a sperm or an ovum. The process of creating a sex cell is meiosis.  

When a sex cell is created in meiosis, the parent’s whole cell more or less divides in two cleaving a sex cell with half of the alleles from the parent. Therefore, if only one trait were to be examined (img.Gamete Selection 1) the result in the haploid daughter cells, would be in each of the two sex cells there would be half of the parent DNA; in this case review a parent with  Aa (heterozygous) in img.Gamete Selection 1.

The parent has a two part sequence which codes for a trait. The trait will express according to the patterns and to the effectiveness of the gene to express itself over others and the frequency with which that gene is expressed and the relationship of the affect and ecology of the individual. A trait does not simply show up, usually. There are many things which contribute to the expression.

A person is put together, genetically like a complex machine. In this example we see nuts and bolts which need both parts to be useful (img.Gamete Selection 1). That is, a parent has two parts in connection that are useful but they can only pass one to the offspring meaning half. The other half will come from the other parent.

When a sex cell is made there are many complex steps which have been covered already in Cells and DNA section you may also recall the added complexity of crossing-over and mixing of the DNA resulting in many unique sex cells from a single person. Therefore, there are many possibilities for the offspring from a parent because the system assures diversity.   

In the following drawings the process and result is simplified, in order to be direct and correct about the process of half the genes, passed onto offspring, by way of meiosis, and intercourse. The outcome is potentially limitless and diversity is assured by the process of life and procreation.

Gamete selection is from one parent. In that, a parent only has the One set of DNA. That DNA is divided into two parts or chromatids. Each chromatid has information but can carry different codes for the same thing such as for blood, or height etc. However, traits are simply controlled by one genetic pairing and there are many more genes. The information for genes is coded in 20,000-25,000 genes which work with others genes creating nearly limitless possibilities.  Tracking these traits is complex See below if we change from 2 sets of two part traits (refer to img.Gamete Selection 3) to 3 sets of two part traits (refer to img.Gamete Selection 4). Then imagine what 25,000 genes may look like.

Answer the following questions. Use the above document only to answer the questions. You can type in the answers if you have made a copy and renamed this document as your own.

 1. Is a bubble diagram the same as factoring but using a picture (refer to img.Gamete Selection 1) ?  two parts. Yes or no and why? (1 pt)

2. What is in the 2 part code/genotype for sex cell 1 and sex cell 2 (refer to img.Gamete Selection 2)?  (1 pt)

3. What is in the 1 part code for sex cell 3 and the 1 part code for sex cell 4 refer to img.Gamete Selection 2)?  (1 pt)

4. If P1 has traits of Aa and Bb then what are the outcomes for the codes for the sex cells, list them there are four ( refer to img.Gamete Selection 3).  (1 pt)

5. Why are pleiotropy and polygenic potentially issues for Mendalian models?  (1 pt)

6. Referring to the drawings in  img.Gamete Selection 4; how is the branch matrix (tree) simpler to identify the parts and outcomes compared to drop-down (bubbles) or the modified FOIL method?  (1 pt)

7. What ways are there to show math processes other than linear expressions or linear equations seen in this section on gametes? There are 5 choices list 3. (3 pt)

8. Would it be helpful to know/learn other ways to do math rather than only equations?  (1 pt)