Essay on Karyotype Lab Report

The first 8 mandatory data columns (listed in the column header line) represent the chromosome

For this assignment, I will use the websites, lab and materials from this week and complete an internet search of my own on chromosomes. I will write a two- page essay that explains how conditions caused by extra or missing chromosomes reflect a meiotic error. I will also choose two conditions or diseases to review. Also, distinguish among the modes of inheritance.

The event in which a tetrad doesn’t split into homologous chromosomes or a homologous chromosome doesn’t split into sister chromatids, which causes an imbalance in the chromosome count of the produced gametes.

Part A: Two genes that are separated by 10 map units show a recombination percentage of

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

Originally, researchers and scientists thought a duplication in the Y chromosome was the connection between how genetics influence crime. The male karyotype would be XYY instead of XY. They have a tendency for hyper-aggressiveness and violence (Wachbroit). This unique karyotype also leads to a significant number of abortions if the fetus carries the karyotype. The other effects of this mutation are men that are taller, less intelligent, hyperactive, and are more impulsive (Wachbroit). After much research no one could relate this to how it

This lab had 2 exercises. Exercise 9.1 involved observing pictures of 60 F2 offspring and recording the phenotypes for 6 different traits. Exercise 9.2 required us to perform the “chi-square test” to determine whether the data we collected matches the standard Mendelian ratio.

a doctor around the hospital will order a special blood test called a karyotype. This test counts the number of chromosomes, this test can also identify any that are abnormally shaped or have some missing pieces.

Later on a male and female haploid cell will join to form a diploid cell with the right number of chromosomes.

You are also provided with a heterozygous female, and a homozygous recessive male for a genetic cross. In this particular female, all the dominant alleles are on one chromosome, and the recessive counterparts are on the other homologous chromosome. Due to a chromosomal condition, in the female no recombination occurs between the M and N loci. Normal recombination occurs between the L and M loci. Diagram this cross, and show the genotypes and frequencies of all offspring expected from this cross.

the genes. If there is a dominant gene that shows up, then the recessive will not show up but

Of the four karyotypes observed, only one was normal. The normal karyotype was the karyotype displayed in Figure one. There were 23 sets of chromosomes, each set containing two chromosomes. There were two karyotypes with an extra chromosome. The karyotype in Figure three had an extra chromosome 21 and the karyotype in Figure four had an extra chromosome 23. There were also two karyotypes displaying an absent chromosome. The karyotype in Figure four was missing a chromosome seven and the karyotype in Figure five was missing a chromosome 23.

Researchers have taken the Y-chromosome of higher primates including humans, and great apes (orangutans, chimpanzees, bonobos, gorillas) and ran analysis research. They have discovered that the X and Y chromosomes recombine only at the pseudo autosomal region (PAR), which is located at the tip of one arm of X and Y chromosome respectively (Wimmer et al., 2005). They have also discovered that due to lack of recombination the Y-chromosome goes through, there is a specific point in the gene where mutations accumulate (MSY) in almost all primates (Wimmer et al., 2005).

The XXY syndrome, most commonly known as Klinefelter syndrome (KS), only affects males of all ages. This syndrome occurs when there is a random genetic error after conception and is not curable, however treatment can help.All females have XX chromosome and all males have XY chromosomes. Unlike the normal XY type that all males have, males affected have an additional X chromosome which results into many symptoms such as impaired spermatogenesis, low testosterone, and male hypogonadism. Since Klinefelter syndrome is related to the sex chromosomes of males, it is a sex link trait.

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