Why Do Offspring Differ from Their Parents?

Meiosis consists of one DNA replication and two nuclear divisions resulting in 4 daughter cells. The process which provides for genetic variation is crossing over. Crossing over occurs in the early stages when homologous chromosomes move together so that their chromatids form a tetrad. This is called synapsis and allows for the exchange of chromosome sections.

Traits get passed down from one generation to the next through Meiosis (cell division), where each parent gives you one Gene for each trait.

2. a) How does meiosis introduce genetic variation into offspring? Think about how the chromosomes line up.(1 point)

Define the term crossing over. (3 points) During meiosis’ prophase the homologous chromatids exchange segments.

A) Meiosis consists of two cell divisions and is broken up into Meiosis I and Meiosis II. At the beginning of the Cell Cycle, in this case there are four chromatids each from the homologous pairs being A, a, B, b. This is the Diploid number (4) meaning it is 2 times the haploid number that will be seen at the end of meiosis II. During the S phase of interphase, the chromatids replicate and reach the end of G2 phase. Now starting meiosis, during the first stage of prophase I the chromosomes condense and pair up through synapsis with their sister chromatids creating AA, aa, BB, bb. After they pair up they go through a process called crossing over, where the homologous chromosomes share a piece of their genetic material with each other. Crossing over allows for the genetic diversity of chromosomes. Now there are four homologous chromosomes Aa, Aa, Bb, Bb, each containing heterozygous alleles because the sister chromatids exchanged genetic information with their homologous pair. During late prophase I, spindle fibers being to form where they will later attach to a homologous chromosomes centromere. The next stage is Metaphase I. During metaphase I, the homologous pairs line up at the metaphase plate, also known to be the center of the cell. The homologous pairs form a tetrad which is considered a group of four homologous chromosomes. These homologous chromosomes orient themselves randomly, which is know as the process of independent

Imagine that you are crossing two plants that are heterozygous for flower color and seed shape. The dominant and recessive alleles for these traits are:

Part B: Genes X, Y, and Z are linked. Crossover gametes between genes X and Y are observed

Human cells carry two copies of each chromosome they have two versions of each gene and the different versions are called alleles. Alleles can be either dominant or recessive. Dominant alleles means you have one copy of the gene or your heterozygous. Recessive alleles means you have two copies of the gene or your homozygous.

Genetics is the study of heredity genes, and traits. Like how our parents' traits and genes are passed down to us. Chromosomes are the huge chunk of genes that wrapped around the proteins. Humans are supposed to have the total of 46 chromosomes. Females have XX chromosomes and males have XY chromosomes. Chromosomes are passed down to offspring, as well as, genes. Also, Genes are strands of DNA; they are like the instructions manuals for our body. Genes are the one that code for the traits. Dominant and recessive traits are the two types of traits are that passed down to the offspring. Usually the offspring show the dominant traits since this trait is a lot stronger than recessive traits. There is a less chance that the offspring will show the recessive traits. Since the recessive traits can only appear if the dominant traits are absent.

The “Baby Face” activity was an activity that required a coin toss to determine what appearance a baby face was going to have. This activity helped us learn about the genetics, traits and characteristics that go ‘behind the scenes’ to determine the appearance of an organism. A characteristic is a feature that has a different form in a population, like hair color or eye color. A trait however, is the different forms of a characteristic, like brown hair and blue eyes. In the activity, a coin toss determined what the baby face appearance would look like in the end, and also in the activity, the coin toss determined the genotype of the baby which affects the phenotype. Genotype, is the combination of genes, while a phenotype is the actual physical

A chromosome is made up of genes, which is sort sections of DNA (Deoxynucleic acid) . Within the genes, there are alleles, which are different forms of a gene. For example the gene for eye colour has an allele for blue eyes and an allele for green eyes. Alleles can be either dominant or recessive. The characteristic controlled by a dominant allele develops if the allele exists

Crossing over in meiosis increases genetic variation in the offspring’s traits. Occurring in interphase one, crossing over is the process

Alleles are a version of a gene, things like hair color, eye color, hitchhiker's thumb, and various other things are controlled by alleles. Alleles are either dominant or recessive, dominant alleles are the one that will show up even if only one parent has it and recessive alleles show up only if the dominant allele isn’t present. Most things are controlled by several different genes but some are controlled only by one.

Phenotypes driven by DNA from passing of traits from parent to offspring. Before children are born, they receive half of their traits from their mother and the other half from their father. That is why the child may have their father’s nose and their mother’s eye shape. Other traits could include eye color, hair color, hair texture, weight, and skin color. Different combinations of traits may cause offspring to appear different from their parents. However, the majority of traits inherited from parents will be the same. There are other things that you do not inherit from parent inherited traits. These are traits that from what the offspring learn or are caused by the environment. Phenotypes is expressed in part through the processes of transcription and translation. In transcription, the cell copies the gene

The two alleles, one contributed by the male and the one by the female gamete remain distinct; alleles do not blend with one another or become altered in any other way