Which of the following statements regarding X inactivation in eutherian mammals is FALSE? X inactivation may occasionally occur in males (tried this answer but marked wrong) This process produces a uniform phenotype in heterozygous females The process appears to be random X inactivation occurs early in embryonic development

Which of the following statements regarding X inactivation in eutherian mammals is FALSE? X inactivation may occasionally occur in males (tried this answer but marked wrong) This process produces a uniform phenotype in heterozygous females The process appears to be random X inactivation occurs early in embryonic development

Human Heredity: Principles and Issues (MindTap Course List)

11th Edition

ISBN:9781305251052

Author:Michael Cummings

Publisher:Michael Cummings

Chapter7: Development And Sex Determination

Section: Chapter Questions

Problem 17QP: Equalizing the Expression of X Chromosome Genes in Males and Females How many Barr bodies would the...

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Why aren't Turners females who have one X chromosome phenotypically normal given that males only have one X and are normal and all female mammals inactivate one of their 2 X chromosomes leaving with one X just like Turners females and these females are also normal, but Turner's females are not normal (have abnormal ovaries). Why?
In ZZ-ZW sex determining systems which of the following is true? Insects such as bees, wasps, and ants use the ZZ-ZW sex determining system. The female is homogametic, while the male is heterogametic. After meiosis in the Female, half the eggs will have the Z chromosome. O The males develop from unfertilized eggs while the females develop from fertilized eggs. The SRY gene is found on the Z chromosome.
In C. elegans there are two sexes: hermaphrodite and male. Sex is determined by the ratio of X chromosomes to haploid sets of autosomes (X/A). An X/A ratio of 1.0 produces a hermaphrodite (XX), and an X/A ratio of 0.5 results in a male (XO). In the 1970s, Jonathan Hodgkin and Sydney Brenner carried out genetic screens to identify mutations in three genes that result in either XX males (tra-1, tra-2) or XO hermaphrodites (her-1). Double-mutant strains were constructed to assess for epistatic interactions between the genes (see table). Propose a genetic model of how the her and tra genes control sex determination.
Which is a FALSE statement about X inactivation in mammalian females? O Females that are heterozygous for an X-linked gene have patches of cells that express one allele and patches of cells that express the other. O Xinactivation is random as to which X is inactivated and takes place early in embryonic development Inactivation is initiated by expression of the Xist gene on the X chromosome that will remain active. Once an X chromosome first becomes inactivated in a cell, that same X will remain inactivated in somatic cells that are descendants of this cell. DOOO
In certain salamanders, the sex of a genetic female can be altered, changing her into a functional male; these salamanders are called sexreversed males. When a sex-reversed male is mated with a normal female, approximately 23 of the offspring are female and 13 are male. How is sex determined in these salamanders? Explain the results of this cross.
Certain genes determine sex, fertility, and viability in Drosophila, and mutations in these genes affect the two sexes differently. Classify the descriptions below based on their occurrence in XY or XX flies. Some descriptions may be used in both categories. The expressed form of Dsx activates maleness genes and represses femaleness genes. XY XX Null mutations in the dsx gene result in an intersex phenotype. Loss-of-function mutations in the tra gene have no effect on phenotype. Sxl is expressed in early embryogenesis from the establishment promoter. Flies that produce Fru-M in brain cells from a transgene perform a mating dance and specifically court females. Loss-of-function mutations in the fru gene result in flies who court both males and females. Sxl regulates splicing of its own RNA to produce a functional protein. The expressed form of Dsx activates femaleness genes and represses maleness genes. Loss-of-function mutations in the Sxl gene have no effect on phenotype. Reset
About 40% of Solomon Islanders carry a gene for blond hair, and yet only 5%–10% of these people actually have blond hair. Why is the number of people with blond hair only 5%–10% when so many people carry genes for blond hair? The duck-billed platypus has a unique mechanism of sex determination: females have five pairs of X chromosomes (X1X1X2X2X3X3X4X4X5X5) and males have five pairs of X and Y chromosomes (X1Y1X2Y2X3Y3X4Y4X5Y5). Do you think each of the X and Y chromosome pairs in males assort independently of other X and Y pairs during meiosis? Why or why not? How is the inheritance of X-linked traits different from the inheritance of autosomal traits? How is the inheritance of X-linked and autosomal traits similar? List as many differences and similarities as you can.
If red vizcacha rats (Tympanoctomys barrerae) have 100 autosomes and 2 sex chromosomes in each of their diploid somatic cells, then they must have: only 102 chromosomes in their haploid germ cells only 100 chromosomes in their haploid germ cells only 52 chromosomes in their haploid germ cells only 51 chromosomes in their haploid germ cells only 50 chromosomes in their haploid germ cells
What specific observations (evidence) support the conclusions about sex determination in Drosophila and humans? Sort each observation to the appropriate bin. If an observation applies to both Drosophila and humans, sort it to the "Both" bin. If an observation does not apply to either Drosophila or humans, sort it to the "Neither" bin. Reset Help Three sets of autosomes per X chromosome are required for male fertility. Sex chromosomes are heteromorphic. Maleness is determined by lack of X chromosomes. Triploid individuals (3n) could be phenotypically normal females. XO individuals are male. More than one Y chromosome is needed for maleness. Diploid XXY individuals are abnormal males. Drosophila only Humans only Both Neither Submit Request Answer
You are studying a new species of insect. You identify the following about sex determination in this species: . Their cells contain chromosomes, but no sex chromosomes • Individuals who produce sperm have half the number of chromosomes than individuals who produce eggs . Changes in the environment do not affect sex determination Given this information, you predict that this species uses sex determination. O XX/XO O parthenogenesis O non-chromosomal O haplo-diploid
In certain salamanders, the sex of a genetic female can be altered, changing her into a functional male; these salamanders are called sex reversed males. When a sex-reversed male is mated with a normal female, approximately 23 of the offspring are female and 13 are male. How is sex determined in these salamanders? Explain the results of this cross
we discuss various mechanisms of sex determination, including the XX/XY system of placental mammals, and the ZZ/ZW system of birds. Monotremes, the most primitive mammals, have a very intriguing sex determination scheme that shares elements of both of these systems. Please use the internet to learn more about how sex in monotremes is determined. Then write a short essay (300-400 words) describing this system and comparing/contrasting it to the XX/XY and ZZ/ZW systems.