Gametes contain how many autosomes




















A genotype with all "recessive" small case genes aabbcc has the lowest amount of melanin and very light skin. Each "dominant" capital gene produces one unit of color, so that a wide range of intermediate skin colors are produced, depending on the number of "dominant" capital genes in the genotype.

For example, a genotype with three "dominant" capital genes and three small case "recessive" genes AaBbCc has a medium amount of melanin and an intermediate skin color. This latter genotype would be characteristic of a mulatto.

In the above cross between two mulatto genotypes AaBbCc x AaBbCc , each parent produces eight different types of gametes and these gametes combine with each other in 64 different ways resulting in a total of seven skin colors. The skin colors can be represented by the number of capital letters, ranging from zero no capital letters to six all capital letters. The approximate shades of skin color corresponding to each genotype are shown in the above table. Note: Skin color may involve at least four pairs of alleles with nine or more shades of skin color.

Each term in the expression represents the number of offspring with a specific skin color phenotype based on the number of capital letters in the genotype. For example, 20 offspring have three capital letters in their genotype and have a skin color that is intermediate between very dark with all caps AABBCC and very light with no caps aabbcc. Questions 69 - These questions refer to the Rh types of Chrissy and John, and their baby boy named Cinco.

Questions 63 - Questions 78 - Remember that the A and B alleles are dominant over the O allele. The type O blood phenotype must be homozygous for the O allele.

Type AB blood phenotype must be heterozygous for the A and B alleles. For these questions, use the process of elimination. Then eliminate the only parents that could have an AB baby, and so forth. Questions 87 - To determine the fractional probability for a taster boy with type B blood, you must make a cross between John and Mary using a genetic checkerboard Punnett square. Questions 91 - Place only decimal values in the squares of your checkerboard because you can't multiply percentages.

The total decimal value for gametes must add up to 1. In other words, 0. The total genotype values must also add up to 1. The following table using 5 coins illustrates these two questions. Simply change the five coins to three coins or children. Remember that sex determination is much more complicated than tossing coins because many other factors are involved. There is only one permutation out of 32 refer to the top permutation, 3rd column from left.

In this example you must consider all possible permutations with 3 Heads and 2 Tails. The 3rd column from left in the above Pascal's Triangle shows 10 permutations out of 32 with 3 Heads and 2 Tails. This is also the probability of having 3 girls and 2 boys when all possible orders are considered. Alleles 0. In garden peas, the gene for round R is dominant over the gene for wrinkled r and the gene for tall T is dominant over the gene for short t. Serious complications may arise when the antibodies of the recipient clump the blood cells of the donor.

Clumping of the donor's blood is indicated by the word "Clump" in the red squares. No clumping of the donor's blood is indicated by the word "None" in the green squares.

None also denotes the lack of anti-A or anti-B antibodies in the type O recipient. It is clear from this chart that the "universal donor" is type O, while the "universal recipient" is type AB. If you include the Rh factor, then the universal donor becomes O Negative while the universal recipient becomes AB Positive. Although it is much more complicated, the Rh blood factor can be explained by a pair of alleles on homologous chromosome pair 1. Like the type O gene, the recessive Rh negative gene - does not produce an antigen.

Because of the time factor involved in building up a concentration titre of antibodies, the first transfusion may not cause any major problems; however, a subsequent transfusion of Rh positive blood could be very serious because the recipient will clump all of the incoming blood cells. Based upon the above table, Rh positive recipients can theoretically receive positive or negative blood, and Rh negative donors can theoretically give to Rh positive and Rh negative recipients.

The following tables explain how to calculate the answers for questions - The data in the tables is slightly different from your exam, but the method of calculation is the same. These questions refer to a cross between two hypothetical watermelons with four pairs of fruit characteristics. In watermelons the gene for green rind G is dominant over the gene for striped rind g , and the gene for short fruit S is dominant over the gene for long fruit s.

The alleles for rind color and fruit length occur on two different pairs of homologous chromosomes. For this question, assume that a gene for large melons L and and gene for many seeds F occur at opposite ends of another chromosome linkage.

The alleles for size and seed number, i. A watermelon plant bearing large, green, short fruits containing many seeds was crossed with a plant bearing large, striped, long fruits containing many seeds. Some of the offspring from this cross produced small, striped, long fruits with few seeds. Assuming no crossing over between homologous chromosomes , what is the fractional chance of producing the following offspring? Remember that there are three pairs of homologous chromosomes in this problem, and one of the homologous pairs exhibits autosomal linkage.

The chromosomes of each parent are shown in the following illustration: There are several ways to solve this problem, but one way is to construct a 16 square checkerboard with eight rows and two columns. Further Exploration Concept Links for further exploration haploid cell chromosome cell division principle of independent assortment gamete Principles of Inheritance.

Related Concepts 7. You have authorized LearnCasting of your reading list in Scitable. Do you want to LearnCast this session? All ova contain one X chromosome and 22 autosomes. Related questions What are four types of chromosomal mutations?

What is the cause of cleft lips and palates? Describe what happens to chromosomes during single and double crossovers. Would we expect to Primitive life likely possessed the elemen.. Life, as we know it today, is presumed to have started in the sea and many of them were likely eukaryotic animal-like or.. Skip to content Main Navigation Search. Dictionary Articles Tutorials Biology Forum. Protein Variety The sequence of amino acids determines the type of protein.

Early Mammals on Earth The Earth's ecosphere was rapidly changing and throwing up a wide range of ecological niches that new adaptive organisms..



0コメント

  • 1000 / 1000